# water discussion..



## Ed

This discussion is going on in another thread and it is over the risk of distilled or reverse osmosis (RO) versus other types of water. Given the frequency of this discussion I thought I should put up some information on why x water is fine, even though so and so said elsewhere it wasn't. 


The original question asked from http://www.dendroboard.com/forum/tree-frogs/70263-pond-frogs-ignore-water.html#post614752



jkooiman said:


> I was wondering why you didn't mention the distilled water Ed. I would love to read any online links you might have. I have always thought distilled water as one of the ultimate "no, no's" in frogkeeping, if I can avoid these damn water stains, let me know! JVK


 
From http://www.dendroboard.com/forum/tree-frogs/70263-pond-frogs-ignore-water.html#post614856 

If we look at the history of the issue, it started with several articles discussing ion loss to severely hypotonic solutions primarily by tiger salamander larvae which were summed up in Amphibian Medicine and Captive Husbandry (2001, Kreiger Press) with the recommendation to not use distilled or RO water with animals as it causes the loss of some ions into the solution (calcium) through the osmoregulation. The more recent data came out in as series of experiments in Ecological and Enviromental Physiology of Amphibians (2009, Oxford Press). In those the studies were run for a longer period and it demonstrated that yes those ions were lost to the solution but the amphibians also were able to actively reabsorb those ions back from solution. The loss is basically energetic unless the amphibian has something compromising the ability to osmoregulate such as septecimias or chytridmycosis. So as long as the amphibian is healthy it is in reality fine to use and you can get away from those calcium stains. 

If we step back and look at it clinically, technically tap water or filtered water or even pond or stream water is also significantly hypoosmotic in potential to the amphibians as the osmolarity of amphibian plasma is much higher than that of those water sources. The impact is the same, the amphibian loses ions to the water and reabsorbs them. Somewhere on forum I think have some of the data on amphibian ringers compared to pedialyte and why pedialyte shouldn't be used in cases of suspected hypocalcemia. 

In animals with compromised abilities to osmoregulate, amphibian ringers is suggested for a number of reason as it reduces stress on the system of the amphibian and in cases of extreme water retention, under the care of a vet, hyperosmotic amphibians ringers are suggested. 

In cases like the above, where the water is coming into contact with a variety of materials the water is als still going to be hypotonic with respect to the amphibian but is going to have picked up stuff from the enclosure which is going to go into solution. 

Does that help? Sorry it isn't on the web for free. 

Ed

From http://www.dendroboard.com/forum/tree-frogs/70263-pond-frogs-ignore-water-2.html#post614934

Just so people have a better understanding of the whole issue about distilled, RO, tap and so forth.. 
The way solutions that may be important in osmoregulation are compared is through osmolarity which can be referenced here (http://en.wikipedia.org/wiki/Osmolarity) (to prevent a lengthy tedious explanation). 
The different types of water used to care for amphibians (RO, DI, tap and even high content mineral waters) have a osmolarity that typically runs from 0 (for RO, DI) up to 28 mOsm/kg (for high content mineral waters) (see www.osmolality.com/pdf/Rave%20Drugs.doc). This is then compared to amphibian ringers which has a rating of 229 mOsm/kg (Amphibian Medicine and Captive Husbandry, 2001 Krieger’s Press), which is considered to be isotonic for the purposes of osmoregulation with amphibian body chemistries. 
As can be seen by the values for water in the paragraph above, regardless of the type of water used, ions will be lost into solution. The degree of loss is going to be of the same scale regardless of the type used as the osmolarity is very similar to one another. The frogs will actively scavenge ions back out of the water (or if the substrate contains mobile calcium and other ions and is moist) from the substrate. This discussion is assuming healthy amphibians and not ill or otherwise compromised ones. 

There is a lot of hype about distilled and RO water that has been continually perpetuated on the internet for a number of years, and I’m sure will continue for quite a long time into the future. 
Some other discussions were held in this thread Dying frog, help please!

Ed 
Reconstituted RO or DI is still going to be less than 28 mOsm/kg unless you get crazy with the dosing.


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## Ed

To sum it all up, RO and DI are fine to use for many of the applications in the enclosures, including but not limited to misting, refilling water bowls or pools and so forth. 

Ed


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## johnc

Sticking my nose in here, but I thought I would add a side opinion. I use nothing but distilled for my thumbnail tads. As a chemist who spent 10 years working on water related chemistry and the chemistry of ions, it's an educated decision. I still don't understand why folks would use anything else for tads that live in tiny aerial pools that are flushed regularly by rain in the wild. Tadpole tea is for ground dwelling tads folks.


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## ZookeeperDoug

I mist with Distilled, fill and flush broms with RO, and use an 80/20 RO/Aged tap in my water feature. I'm guessing our vivariums are quickly leaching all kinds of ions from the wood, plants, hydroton, leaves, etc back into any water that the actual assumed deliterious effects of RO/Dostilled use wouldn't ever be realized anyway.

Great post Ed.

JohnC

I agree. Rainwater is essentially distilled water and is what fills broms naturally in the wild. Now I'm not quite up to speed on raising thumbs but the only thing I can see is if the volume of water that the tads are raised in is much greater than a typical brom axil, perhaps that large about of super clean water could pull more ions out of the tad before an equillibrium is reached. Then again, as Ed says the tads probably actively uptake ions and as long as they are healthy there is probably no worry.


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## frogmanchu

Ed thanks for the info. For all else thank you also. I want the best for my frogs so I figured I'd see what works for everyone. I have tons more reading to do now . Once agian thanks guys


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## Judy S

Ed, don't get a swelled head...but I hope you can see just how important your contributions are. It does not appear to me that the "others" in this field either care or want to participate in informing or educating "us" to better husbandry of our frogs....thanks for your imput...


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## frogmanchu

Ed is the bomb lol. Ed keep hitting us with the good word man. If no one else listens I will.


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## PRIZMHEAD

so getting a RO/DI unit would be ok to use for all the water in the tank ?


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## Ed

PRIZMHEAD said:


> so getting a RO/DI unit would be ok to use for all the water in the tank ?


What did the summary in the second post in the thread say? 

Some comments 

Ed


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## PRIZMHEAD

Thx


Sent from my iPhone using Tapatalk


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## Anapsid

I have been using distilled for a month now with my new dart frogs as I was told by my vet and the distributor that was what to use if I cannot get ahold of R/O water, then read in a book I just bought about distilled being deadly. So to be 100% clear, its perfectly fine for me to be only using distilled? I don't mean to get repetitive, I'm just new and paranoid. Also, I was wondering, is it really necessary for leucs to have a water dish? I was initially told no, but I see a lot of discussion about having water dishes on the boards.


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## Ed

Anapsid said:


> I have been using distilled for a month now with my new dart frogs as I was told by my vet and the distributor that was what to use if I cannot get ahold of R/O water, then read in a book I just bought about distilled being deadly. So to be 100% clear, its perfectly fine for me to be only using distilled? I don't mean to get repetitive, I'm just new and paranoid. Also, I was wondering, is it really necessary for leucs to have a water dish? I was initially told no, but I see a lot of discussion about having water dishes on the boards.


The first and second posts should answer your question as to safety. As for needing a water bowl, they don't need a water bowl unless you are giving them an option to deposit tadpoles. 

Some comments 

Ed


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## Wusserton

Anapsid said:


> I have been using distilled for a month now with my new dart frogs as I was told by my vet and the distributor that was what to use if I cannot get ahold of R/O water, then read in a book I just bought about distilled being deadly. So to be 100% clear, its perfectly fine for me to be only using distilled? I don't mean to get repetitive, I'm just new and paranoid. Also, I was wondering, is it really necessary for leucs to have a water dish? I was initially told no, but I see a lot of discussion about having water dishes on the boards.


I use nothing but distilled water and have never had problems but out of cost concerns over time im looking at RO as an alternative, if you are brewing some beer in your basement and perfected a distillery that pumps out 10g a week than let me know lol otherwise Im moving to RO vs DI at $20+ a month! still cheap so no hurries lol


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## JunF

Ed said:


> To sum it all up, RO and DI are fine to use for many of the applications in the enclosures, including but not limited to misting, refilling water bowls or pools and so forth.
> 
> Ed





Ed said:


> To sum it all up, RO and DI are fine to use for many of the applications in the enclosures, including but not limited to misting, refilling water bowls or pools and so forth.
> 
> Ed


Good Day, have you read any articles related to the uses of the liquid from water changes in fresh water fish tanks in regards to frog care? What’s your opinion on the topic?


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## Socratic Monologue

JunF said:


> Good Day, have you read any articles related to the uses of the liquid from water changes in fresh water fish tanks in regards to frog care? What’s your opinion on the topic?


Don't do it. Pathogens can be transmitted between fish and frogs, and frogs are sensitive to nitrogenous waste compounds that are the very reason water changes are made in a fish tank. Fish tank water is waste water.


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## Ukee

OK, so here is a hypothetical question: I live in an area where we get 4+ meters of rain per year. Can I collect rainwater and use it instead of distilled or RO or whatever?


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## Encyclia

Not typically recommended. That rain falls through some pretty nasty stuff even if the catch is clean. Less risk to use filtration options that you can control. The amount of rainfall that you get doesn't really matter.

Mark


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## Ukee

Thanks for the reply. I live in a pretty remote area where distilled and RO water are essentially unavailable, but rainwater is not! As far as rain water bringing down airborne pollutants, it's non-issue out here - there is no industry for a hundred miles around us (I'm on the west coast of Vancouver Island, regional population <5k and essentially zero pollution). I had a thought that I could divert rainwater into a large barrel, let it settle, and then simply filter it through a Brita or something and use it to mist. Is your objection based on airborne particulate?


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## Socratic Monologue

Distance from sources doesn't matter much at all. Here in the upper midwest of the USA, we get smoke from California and dust from Africa every few years. Non particulate pollution such as sulfur dioxide is known to travel over 1000 miles. 

Most of these sources are periodic, so you could use collected rainwater for months or years and then catch a batch of smoke from burning vinyl siding in California, or from industrial pollution that reaches your location following a shift in weather patterns (becoming more common, I read) and lose all your animals. 

One benefit to RO, especially RO that you produce yourself, is for troubleshooting future problems -- whatever issue comes up (frog death, plant issues, microfauna crash, algae growth) if you know the quality of your water you can eliminate that as a possible cause for the trouble and move forward identifying the true cause. Running one's own RO filter, changing the filters on schedule and having an inexpensive TDS meter to monitor the membrane, is well worth the peace of mind, IME.


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## Anda

Ok, I see and understand the logic and possible eventualities. Would this make the rainwater they are exposed to in the wild potentially deadly as well?

I too live in a remote area, at 69 degrees north and have never heard of polluted rainwater occurring here. It also contains micronutrients from what I understand? 
Learn new things here every day for sure, but in this instance I am willing to take the risk.


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## Robru

Socratic Monologue said:


> Running one's own RO filter, changing the filters on schedule and having an inexpensive TDS meter to monitor the membrane, is well worth the peace of mind, IME.























I always have about 100L of RO water in stock


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## Socratic Monologue

Anda said:


> Would this make the rainwater they are exposed to in the wild potentially deadly as well?


Amphibians around the world are dying at incredible rates. No one thinks that air pollution (which moves along the same system that causes rain) isn't implicated, but I'm willing to bet that data are hard to come by.



Anda said:


> I too live in a remote area, at 69 degrees north and have never heard of polluted rainwater occurring here.


*"Even though Sweden* has one of Europe’s lowest levels of air pollution, each year about 7600 people die prematurely due to exposure to air pollutants, primarily nitrogen dioxide and particulate matter"

source: Swedes harmed by air pollution | Airclim

"Until relatively recently air pollution has been seen as a local issue. It was in southern Scandinavia in the late 1950's that the problems of acid rain were first observed and it was then that people began to realise that the origins of this pollution were far away in Britain and Northern Europe. One early answer to industrial air pollution was to build very tall chimneys. Unfortunately all this does is push the polluting gases up into the clouds allowing emissions to float away on the wind. The wind carries the pollution many hundreds of miles away where it eventually falls as acid rain. In this way Britain has contributed at least 16% of the acid deposition in Norway. Over ninety percent of Norway's acid pollution comes from other countries. The worst European polluters are Germany, UK, Poland and Spain, each of them producing over a million tons of sulphur emissions in 1994.


source:What is Acid Rain?

Air pollution and harm to tree growth in Scandinavia: Forest growth and critical air pollutant loads in Scandinavia

And, why air pollution fits into the rainwater concern:

"As a raindrop falls through the atmosphere, it can attract tens to hundreds of tiny aerosol particles to its surface before hitting the ground. The process by which droplets and aerosols attract is coagulation, a natural phenomenon that can act to clear the air of pollutants like soot, sulfates, and organic particles."









Can rain clean the atmosphere?


Atmospheric chemists at MIT have determined how effective rain is in cleaning the atmosphere. Given the altitude of a cloud, the size of its droplets, and the diameter and concentration of aerosols, the team can predict the likelihood that a raindrop will sweep a particle out of the atmosphere.




news.mit.edu


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## Anda

By all means, I would be surprised too if rain was not part of the equation, but the reason I wrote what I did was because of a claim that a single dose of rainwater is potentially deadly. This is highly unlikely where I live. As for acid rain it is one of the great Scandinavian environmental success stories of the last century. It is all but gone and never existed where I live. In Canada as well, most of the SO2 producing plants and smelters are under strict regulations, polluting a lot less then they were 30 years ago. Local air pollution in cities (PM for the most part) has increased many places.

Frogs disappearing globally is a tragedy and a very important issue. If rain composition was a global uniform issue, then maybe, but it is not. It is more complex, likely related to climate change and perhaps radiation? Both contributing to habitat destruction and disruption. I would be very interested to learn more about this.


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## Robru

*Sweet rain because acid rain has disappeared? (2019)*
Acid rain has been a hot topic for a while, because this form of rain is very bad for the environment. You've heard less about it lately. Is it because acid rain has completely disappeared?

*What is acid rain?*
What exactly is acid rain? Acid rain is caused by exhaust fumes in the air. These are harmful substances such as nitrogen, sulfur dioxide and ammonia. Because these substances remain in the air, they dissolve in clouds and a chemical reaction takes place. And when it starts to rain, these substances are also released. This is called acid rain. This rain is harmful to forests and lakes, for example.










*Has Acid Rain Really Gone?*
Since the 1980s, there has been a lot of attention for acid rain, as this form of rain is so bad for our environment. By reducing emissions of the said harmful substances into the air, the hope was that acid rain would disappear. Various measures have been taken. For example, today houses are heated by gas instead of coal. And sulfur dioxide is extracted from flue gas in power stations. Ammonia emissions have also decreased and the introduction of the three-way catalytic converter to passenger cars resulted in a 40% reduction in nitrogen oxides emissions. These measures have ensured that our air is cleaned of sulfur.

*Sweet rain*
Because of these measures, acid rain has made way for sweet rain. Sweet rain is rain as it should be, without harmful substances. Yet it is not the case that acid rain has completely disappeared. Because we have suffered from acid rain for such a time, the soil is still acidic. Thanks to the measures, sweet rain is falling again, but soil acidification is still continuing in some places.


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## Socratic Monologue

Anda said:


> a claim that a single dose of rainwater is potentially deadly.


No one in the current discussion (the one started two days ago) claimed anything about a single usage. This was a necropost of a discussion over the risk of hypotonic water (that there is none), and maybe single dose claims were made there. I myself went out of my way to explain how it is the long term use of water that is not monitored -- and the risk of episodic contamination because of the lack of constant monitoring -- is problematic.


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## Anda

I am absolutely convinced that RO water is preferable to rainwater for most of the frog keepers on this forum. Just as I am certain that there are exeptions. Although RO has no risks, there might be benefits with clean rainwater. Since this is a discussion forum, I thought it worth while to discuss it


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## Chris S

Socratic Monologue said:


> No one in the current discussion (the one started two days ago) claimed anything about a single usage. This was a necropost of a discussion over the risk of hypotonic water (that there is none), and maybe single dose claims were made there. I myself went out of my way to explain how it is the long term use of water that is not monitored -- and the risk of episodic contamination because of the lack of constant monitoring -- is problematic.


And also important to remember that we are dealing with small contained environments that do not have the ability to process and breakdown many pollutants in the same manner a forest or jungle ecosystem can, so their potential impact is likely magnified many times in the this scenario.


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## Robru

What are the Downsides of Reverse Osmosis?

1. For every liter of water produced from reverse osmosis, 3 to 5 liters are discarded. This makes the process wasteful and relatively expensive.
2. Many reverse osmosis systems are plastic and require electricity to work properly.
3. The process is very slow. Many systems do not produce more than 15 liters of water per day and are therefore only used for drinking water and not for the whole house and for showering.
4. Almost all minerals are removed.
5. The installation process is quite complicated and professional help is often indispensable. It takes up a relatively large amount of space.
6. The system should be thoroughly cleaned once a year and fitted with new filters once or twice a year.
7. The vitality of the water decreases sharply in the total filtration process.


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## Socratic Monologue

Chris S said:


> And also important to remember that we are dealing with small contained environments that do not have the ability to process and breakdown many pollutants in the same manner a forest or jungle ecosystem can, so their potential impact is likely magnified many times in the this scenario.


Agree. Also, collecting rainwater is different than natural rainfall. A pollution incident that only lasts a couple days (such as the 2011 volcanic eruption in Iceland that sent an ash plume over Scandinavia) could happen during a rainwater collection cycle (some, I'd even wager _most_, concentrated pollution releases go undetected by the general public) and be used in the viv for weeks or more, whereas in a natural setting the next rainfall would wash at least some of those pollutants away.


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## Socratic Monologue

Robru said:


> vitality


What is that?


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## Robru

Socratic Monologue said:


> What is that?


*Vitalizing? What exactly is that?*
Health is high on the agenda for all of us. Good health must be cherished and that is why we nowadays deal consciously with our food and our way of life. Unfortunately, our drinking water is often neglected in this socially important theme. With this we are doing ourselves quite short. Water is an essential part of our body and we simply cannot live without it. So why not invest in our drinking water? With this you invest directly in your own health.

The water as it comes from our tap can become vital water. You can also vitalise your tap water. This sounds very complicated, but it certainly is not. First of all, it is good to know exactly what vitalizing is.

*The explanation*
We take you back to the basics of water. To be precise, to water in its purest form. A good example of water in its purest form is the melt water that finds its way down from the mountains in a stream or river. The structure of this water is very different from the structure of our drinking water. After all, the meltwater from the mountains only has to do with natural conditions. It should be clear that this is not the case with our drinking water. Think of processes such as pumping up and pumping water, treating water by means of irradiation, filtering water, and so on. All these processes break down the original structure of water and ultimately affect the quality of the water. Our tap water contains harmful vibrations. In fact, vitalizing means nothing more than returning this original structure to our drinking water. By vitalizing our water, harmful vibrations are removed from the water and this naturally benefits your health. The orderly structure of vital water also means that the body is supplied with energy. The uniform water molecules that make up this structure do not disturb each other and vibrate together with one frequency, that is, they resonate, producing much more energy than with chaotic movements. This can easily be seen under the microscope or often tasted in the soft taste of the water.


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## Socratic Monologue

Sorry, that's pseudoscience. Not relevant at all.


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## Anda

Ok, I find this very categorical. 
To me does not make sense to plan animal husbandry around events that take place every 80 years or so.

A pure question: could it be that the RO process removes potentially benefitial substances?


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## Socratic Monologue

Anda said:


> A pure question: could it be that the RO process removes potentially benefitial substances?


RO removes everything that is not water, so the answer would have to be 'yes'. For some applications, substances are added back to RO water (fertilizers for non-viv plant use, minerals for drinking water purposes, reagents for lab purposes, etc), but there is yet to be developed any more efficient, more effective, cheaper, and less energy intensive method to purify water for the specific aims of vivarium use (i.e. remove nearly all of most possible toxins, the vast majority of bacteria and fungi, and 95%+ of water-spot-causing carbonate minerals).


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## Robru

Socratic Monologue said:


> Sorry, that's pseudoscience. Not relevant at all.


Sorry, I just wanted to clarify the word vitality in connection with water


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## Robru

Anda said:


> A pure question: could it be that the RO process removes potentially benefitial substances?


Yes, so the product should *not* be used for human consumption. It would start immediately, extracting minerals from your body.


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## Encyclia

You guys that want to collect rain water are welcome to do so. I would never do that. There are so many things that are out of my control if I try to do that (I don't get enough rain to do it, so it is a moot point for me). You may think that the pollution issue is not important, but I think you are underestimating the risks, both airborne and what happens to the water once it is caught. 

In my experience, @Robru's list of RO unit downsides has grains of truth (and some eye-rollers) but I don't find those things compelling relative to the benefits for the purpose of dart frog husbandry. The one exception is the water use issue. That is real. I do pipe my waste water up onto my lawn during the time of year that it isn't too cold, but the rest of the year, that water is wasted, that is true. Also, @Robru is probably right that you shouldn't be drinking RO or distilled water exclusively unless a physician tells you to.

Mark


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## Kmc

Wouldnt it be cool if a herp care co. put together a reconstitute of amphibian's ringers? In packets. And like legit.


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## Robru

Encyclia said:


> You guys that want to collect rain water are welcome to do so. I would never do that. There are so many things that are out of my control if I try to do that (I don't get enough rain to do it, so it is a moot point for me). You may think that the pollution issue is not important, but I think you are underestimating the risks, both airborne and what happens to the water once it is caught.


Mark's story has a great grain of truth, you have little control over what 'foreign' substances are in rainwater, which really shouldn't be there.

But ... our poison dart frogs are also not covered by clean rainwater in the Amazon rainforests:
It turns out to be the main source of acid rain in these remote areas. Take the Amazon, for example. In summer, rain here becomes up to 80 percent more acidic than normal. That is enormous and even more acidic than in the US where the acidity remains at 30 percent over the same time.


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## Encyclia

This is a fair point. I think there probably is some "bad" water that falls on frogs in their native habitat. I think, though, that frogs are subsisting in these environments in spite of the negative environmental problems, not because of them. Native habitat also has processes that can filter the water to some degree and mitigate the direct exposure of the frogs to the water. Our tanks can't do this nearly as effectively. Just because native frogs are exposed to something bad doesn't mean that we need to duplicate that aspect of the native environment in our vivaria. Frogs are dying off in huge numbers in their native habitats due to a variety of impacts to their native ecosystems. Why would we not try to make their environment better in captivity than the known problems with their disturbed native ecosystems? Just because the frogs have to suffer through clearly sub-optimal conditions in their native habitat doesn't mean that we need to duplicate these conditions in our tanks. If we can do better, we should. I think that clean water is doing better.

Mark


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## Anda

Have read up on the issue and contacted the Norwegian water authorities for a comment. When water evaporates it is basically distilled and completely clean. The contamination process happens as the rain falls through the sky on the way down, coming in contact with potential contaminants. Mostly these are acidic molecules that cause acid rain and some particulate matter (PM). In very specific and polluted areas other molecules such as PFAS (flame retardants) may also become part of the rain drop.


The rain where I live is not contaminated with either acidic molecules or environmental contaminants. Even in case of long-range transport of ash or sand, not enough to make the rain acutely toxic for organisms. The rain that fall here consistently has a PH of 5.5 which is the same as your OR water after it has been in contact with air.
As someone correctly pointed out the rain may be clean, but the rainwater that ends up in your reservoir is not. This is where the pollution happens. So unless you are absolutely sure that your collection method is clean you might end up with a contaminated terrarium. (Collecting fresh snow would eliminate this problem, but that is not for everyone).
Since one has only bioaccumulation in the terrarium, not biomagnification it is extremely unlikely that concentrations of contaminants will build up sufficiently to harm living organisms if your rain and collection method is clean.

All in all, after some consideration, I would be extremely restrictive in the use of collected rainwater.

But, I would also be very concerned with using only RO water without making sure that the frogs had access to/were replenished with minerals and trace elements that are necessarily washed out through their permeable skin. In addition, RO water that has not been in contact with air contains no oxygen and has a PH much higher than the frogs would be exposed to in nature (although the replenishing process happens rather quickly).


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## Robru

Anda said:


> The rain that fall here consistently has a PH of 5.5 which is the same as your OR water after it has been in contact with air.


The water that comes out of the osmosis machine is pH neutral and therefore has a pH value of 7.

The frog's skin is thin, moist and contains many blood vessels. Frogs drink and breathe through the skin. They do not swallow water, they get all the water they need through their skin and by eating food animals.


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## Anda

Robru said:


> Reverse osmosis water is nearly pure water with a PH of *7*.


Agreed, but it only needs a reatively short exposure time to air to become 5.5 again. 10 minutes in ideal conditions, but much more in a tank of course.


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## Robru

Anda said:


> but it only needs a reatively short exposure time to air to become 5.5 again. 10 minutes in ideal conditions, but much more in a tank of course.


The PH value will indeed change when it comes into contact with another substance such as the substrate.

But back to the advice in this topic: RO water is used because it is *clean*, so it will not transfer diseases and contaminants quickly. And as a plus, no limescale deposits on plant leaves, which by the way will not bother you with rainwater.


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## Anda

I believe we are in agreement, but there is also the element of being too clean and sterile.

Before I used RO water I would make sure to bring it back to the PH and oxygen characteristics of rainwater. This would easily be accomplished with a small circulation pump un the RO reservoir while exposed to air. 

And one more question. Neither the RO water nor the plant-based substrate in a terrarium will release sufficient salts, minerals or trace elements. I also seem to remember that these resources are very scarce in the rainforests. Is it believed that the frogs acquire all needed substances through food?


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## Robru

Anda said:


> And one more question. Neither the RO water nor the plant-based substrate in a terrarium will release sufficient salts, minerals or trace elements. I also seem to remember that these resources are very scarce in the rainforests. Is it believed that the frogs acquire all needed substances through food?


I don't really dare to make a statement about this. But I think the necessary substances come from the food and preparation additives.


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## Socratic Monologue

The pH of RO water is irrelevant. It varies from 7 down depending on CO2 concentration, which affects neither the frogs nor the plants in the situations in which we use it (atmospheric CO2). It is simply a non-issue. The pH of rainwater is driven in part by SO2 and nitrogen oxides, which are issues.

The pH of very pure (i.e. RO) water is a theoretical determination (it is 7), in part since pH probes don't behave reliably in pure water because there are no ions to measure (the pH of water is a mathematical relationship between free H+ and OH- ions). Not that the concentration of oxygen is relevant (and it does not affect pH) relevant, but RO water contains plenty of oxygen, since RO processing does not remove dissolved gases, and pressurized source water is typically supersaturated with dissolved atmospheric gases. All this can be easily confirmed by a simple web search.

RO water and ABG and frog poop has been shown by thousands of keepers over decades to reliably grow many species of plants really, really well.

Frogs can move ions through their drinking patch (and, likely, ions move through their skin constantly, which is one reason why the purity of the water that is forced on them in captivity is so important), which is one reason some keepers are seeing benefits from various applications of clay and similar substrates. Given the frequency with which we see threads here regarding build up of supplement dust in vivs, dart frog vivs substrate likely becomes high in salts, etc. fairly quickly. 

As to the 'minerals washed out through skin' claim (which I take to refer to passive ion loss, which active ion transport mechanisms counter), to prevent this by applying only isotonic (i.e. haing the same mineral content as frog blood plasma) liquids to the viv would be disastrous. The osmotic pressure difference relative to frog plasma of RO water and rain water is nearly the same and would make no little physiological difference.


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## Encyclia

Did you guys read the early posts in this thread? They address concerns about RO and distilled being bad for frog husbandry. RO water doesn't have magic properties that make it permanently a certain way. As @Robru said, the water is interacting with its environment as soon as it goes into the tank. Gas concentrations are dynamic and the water will quickly move to an equilibrium for all gasses and mineral content once introduced to the tank. The water doesn't stay sterile permanently - it is quickly modified by its environment, especially when it is being introduced in very small droplets (mist from our misters). I think that RO water would be pretty similar to other kinds of water (rain? tap?) in the tank after a fairly short time period.

Mark


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## Anda

Thank you for the information in the process only removing CO2, not O2, that is informative.

PH7 may be an non-issue, but natural clean rain that frogs are exposed to in nature has a PH of 5.5 which is 32 times more acidic that than PH neutral RO water. I think the question may be warranted at least. (Or in light of the new post, if this happens rather instantly through misting, then maybe not.)

I will look up more info on adding clay.


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## Socratic Monologue

Anda said:


> Thank you for the information in the process only removing CO2, not O2, that is informative.


Apparently I wasn't clear. RO membranes do not remove any dissolved gases, neither CO2 nor O2 (nor N2, nor Rn, nor Cl, etc). Other, sometimes associated, methods do remove some of these (e.g. activated carbon can remove Cl) but I don't know of any practical way to get dissolved CO2 or O2 below atmospheric concentrations (degassing with air preprocessed by a sodium hydroxide based CO2 scrubber would be one way, though very cumbersome and materials-intensive).

Again, none of that is relevant to dart keeping. I'd highly recommend that novice keepers at least try the established practices that have been worked out over many years by many keepers. Very few reinventions of the wheel have positive outcomes, especially when pursued without much understanding of the need for doing so. I apologize if that comes off as harsh, but many of the concerns that have been raised here are based in simple factual error, and many of the rest can be shown by experience to be irrelevant. I'm not sure how to say this more respectfully; if I could, I would.


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## Anda

You were clear, but I got confused when reading this earlier: https://www.123filter.com/ac/why-reverse-osmosis-water-is-acidic

No worries, I was convinced that my natural rain collection method was ideal, but see that I was wrong. That being said, I hope there will be some new wheel-reinventions down the road in some aspects of frog keeping, it would be boring to have all the answers


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## Encyclia

I look forward to this too, @Anda! If you look back at the last decade or so in keeping, there have been some really important changes to the hobby with huge implications to the health of our animals. A few that come to mind are 1) better supplementation that has almost eliminated problems like spindly leg syndrome 2) LED lighting that has made it much safer for the frogs to avoid heat exposure and 3) better understanding of ventilation and humidity in our tanks (though some of this progress has been eroded by trends in social media influencers showing tank designs that don't reflect best husbandry practices). I am absolutely certain there are lots of things left to be discovered in dart frog keeping!

Mark


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## Robru

Anda said:


> No worries, I was convinced that my natural rain collection method was ideal, but see that I was wrong. That being said, I hope there will be some new wheel-reinventions down the road in some aspects of frog keeping, it would be boring to have all the answer


You are right about that. Let's keep looking ahead and get more and more knowledge, then we will be better able to keep frogs and other animals indoors


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## Ukee

I have read the many posts that have popped up since I first posted with great interest. My conclusion would be that in some cases rain water may be totally fine, especially if it is collected in a clean receptacle, and even more so if it subsequently filtered.
Where I live on Vancouver Island, we receive 4+ meters of rain per year. There is minimal industry / airborne pollution around here. While I readily recognize that some airborne pollutants can indeed travel thousands of kilometers, it seems unlikely that they could possible naturally concentrate in any harmful levels. Assuming the rain water is further filtered through activated charcoal (for example), whatever trace amounts of harmful chemicals or toxins remain would seem extremely unlikely to pose any threat. The abundance and diversity of indigenous amphibain species that thrive here would suggest as much. 
The point about bioaccumulation is factually incorrect. Dissolved substances _could_ accumulate in a system in which water was continually added and allowed to evaporate (how hard water stains form in a kettle), but in a vivarium the water is constantly replaced. The vast majority percolates through the substrate and is drained out, the rest is transpired by the plants / frogs, and in neither case would anything accumulate. 
I do not disagree with the notion that RO water is pure and safe and offers a certain peace of mind, but I do find it hard to believe that even an amphibian could be so susceptible to microdoses of contaminants in rain water that you could see adverse effects in a vivarium environment. 
I would be very interested to learn more about the possible role of airborne pollutants in amphibian declines. The majority of research on water-borne pollutants seems to focus on substances introduced or leached into the water table rather than released into the air.


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## Anda

Yes, I agree and wrote that bioaccumulation could happen in a terrarium, but not biomagnification since there is no real food chain. Then again there are the clean up crews... 

In any case I just ordered my first RO unit.


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