# What's wrong with screen top?



## serial hobbiest (Mar 5, 2017)

Hey everyone.
Before I go and pay for something not really necessary, I'd like to ask if anyone has their humidity under control without using a mostly enclosed vivarium cover. Once upon a time, I thought I wanted a chameleon, which also has high humidity requirements, but after much research, I learned that enclosing them in glass is a big non-no. Instead you rely on the evapo-transpiration from the plants and the misting system to maintain humidity within a screen enclosure. So, if this is possible for chameleon care, why not frogs?

Considering the animals live above a layer of water, amongst plants, receive lots of misting, and have absorbent coco coir for a background which will never get a chance to dry, how can low humidity even be concern? Maybe I'd have to double the misting frequency, or something, but it is really that big of a deal?

So, after you straighten me out on this topic and convince me to enclose everything except for a small strip of mesh, would simply getting a piece of glass, or acrylic cut to fit the Exo-terra top above the existing screen suffice?
I have an 18" 6400K LED Sunblaster for a 24" tall viv. Will my red earthstars stay red with light being filtered through glass and mesh?

Thanks!
-Jason


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## Grimsrude (Apr 6, 2017)

serial hobbiest said:


> ...
> 
> So, after you straighten me out on this topic and convince me to enclose everything except for a small strip of mesh, would simply getting a piece of glass, or acrylic cut to fit the Exo-terra top above the existing screen suffice?
> I have an 18" 6400K LED Sunblaster for a 24" tall viv. ...
> ...


I don't know much about the specifics of your first concern. 

As for the second, NEHerp actually sells cut glass panels for the tops for this very purpose - some people use glass, I'd suggest against acrylic as it would potentially warp, especially under the heat of lamps. Alternatively, if you're lookign for a quick fix, many people (including myself) just use tin foil. I had that for my exo terra enclosure for my ball python until I decided to get some cut glass.


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## Dane (Aug 19, 2004)

If you could maintain proper humidity, and keep your frogs in an all-screen cage (like the do in most South American frog 'farms'), I'd say go for it. One of our local San Diego froggers (DB screen name ErikS), has some of the nicest enclosures I've ever seen, and he runs his Exos with a full screen top. It does make it more difficult to regulate humidity, so there may be some trial and error, and automated misting would be a must.


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## Bfrog (May 5, 2010)

There's a big difference in the two regarding needs and air circulation. Dart frogs live near the forest floor where there is more humidity while Chameleons live up in the trees typically and require significantly more air flow. Chameleons live in madagascar while dart frogs live in Central and South America... while both tropical, those are two very different environments. Dart frogs have significantly higher humidity requirements than chameleons... and completely different physiology. 

The best airflow for dart frogs is a small vent screen or internal air circulation using computer fans to circulate the air and prevent it from becoming stale/stagnant. A small vent (like 1") near the bottom and another one at the top along with frequent misting would be ideal for dart frogs but way too humid for chameleons. Even with 20 gallon vertical tanks and 3" ventilation screens coupled with frequent misting, I need to mist my tanks daily to keep the plants and frogs happy. No airflow is probably better for dart frogs than too much as humidity levels directly affect respiration and nutrient absorption in amphibians as well... but of course some airflow, the right amount, is always the best practice.

Screen tops will cause things to dry out, allow plants to get burned by the lights and make balance much more difficult to achieve. It'll affect your microfauna too. I've done both but a screen top has never been enough for dart frogs. Try to avoid looping all tropical species and their needs together... it's an oversimplified, faulty comparison.

A proper top is cheaper and better use of money than replacing frogs....just like proper airflow for chameleons is better than trying to force them to live in too much humidity and stagnant air.

the light should be fine.


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## Grimsrude (Apr 6, 2017)

After looking at things a bit - I think the difference is the amount of airflow and how consistant the humidity is. I don't own or know much about Chameleons, but I imagine they don't like being wet, but they need the humidity. So they need a screen cage with lots of watering to allow them to dry after each soak. 

Frogs on the other hand, almost need to be wet. Humidity can stand to be between 70-90%, but their skin is far more fragile and sensitive to changes in humidity. Add to that, having lots of ventalation usually means things dry out - unless you've got an absolutely huge vivarium, chances are, within an hour, everything in that tank will be nearly dry to the touch (excluding substrate - soil humidity is a different story). I experience that when I just leave the front door open on my cage - my house isn't particularly dry (40% humidity) but even then, leaving the door open for an hour tends to match the two and wic out all the moisture from the surfaces. 

But again - I'm no expert on exactly what Chams vs dart frogs (or most other herps/amphibians for that matter) need a more closed on cage. So take what I've said with an moderately educated grain of salt!

Edit: heh, well, I was sort of right, someone posted just as I was making this second post  Good explanation Bfrog!


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## Pumilo (Sep 4, 2010)

Acrylic would warp, not because of heat, but due to moisture. Acrylic absorbs moisture. When it absorbs water, it expands. Your problem comes because you have one side facing the humid viv, absorbing water. The other side is facing a dry room. This means one side expands, while the dry side does not. This forces your acrylic to warp with the edges and corners ALWAYS warping UP, never down, so it sits like a bowl on top of your viv.. 

If it were warping due to heat, then the top surface would get hotter than the bottom. That would expand the top surface, forcing the warp to occur exactly the opposite, so that your lid sits like an upside down bowl.

Theoretically, it would be possible to have a screen top, but I don't advise it. First off, why would we keep a frog the same way we keep a chameleon? Keep your chameleon the way it's recommended for chameleons, but for frogs, perhaps think about keeping them the way that other successful frog keepers have found success, yes?
If you go that route, your viv will have to be BUILT. You will need to take special precautions and build in many microclimate zones, for your frogs to hang out it, and be prepared, chances are high that they will spend a good amount of time hiding out, unseen, in the cryptic areas of the viv.
Doubling your misting will probably not be enough. I believe you would need to do many, very short misting cycles throughout the day. Hopefully it will maintain enough humidity in the cryptic zones overnight, because you really don't want to mist at night. Sure it rains at night, outside, but we aren't outside. We don't have the same breezes to dry it off the plants. We don't mist at night, because standing water on the plants is not healthy for them.
Your substrate will have to be both exceptionally well drained, but still hold high levels of moisture. You'll likely be relying on your substrate to hold the humidity up. I would highly advise a homemade, calcium bearing clay substrate if you try this. They hold more water, helping keep humidity levels up.

Possible, yes. Advisable, no. I would not try it.


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## serial hobbiest (Mar 5, 2017)

Okay, thanks everyone. Glass it is.

With no forced air circulation, will a 1" screen at the top, plus the front vent in an Exo-Terra terrarium suffice for ventilation, should I ever end up with a pickier plant?

If I seal up my top so that it's un-openable, (or place the viv in a location where the top in rather inaccessible regardless), is there much concern of frogs jumping out the front door when I open it up to feed them? I only plan to get two D. tinctorius azureus.


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## Ed (Sep 19, 2004)

As long as the humidity is above 60% then a full screen top is fine with the frogs. 

A sealed enclosure with built in fans can still be stagnant since if the humidity approaches 100% it will take a very longtime to evaporate off of the plants which can cause significant problems for the frogs. Fans are best used in conjunction with some form of air exchange with outside the enclosure (passive or active). 

If you consider the physiology of the frogs the reason they can do just fine in 60% humidity is because they are at the same time able to uptake moisture directly from the substrate and transport it to the skin where it evaporates cooling the frog. The greater the humidity the greater the reduction of the frog to use this process to control its body temperature. 

In general if you have too much ventilation it is easy to cover up (example a piece of glass cut to fit) than it is if you have too little. 

some comments 

Ed


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## kimcmich (Jan 17, 2016)

@serial_hobbyist,

I have a large viv 5 feet x5 feet x2.5 feet with an open top. During the day, my misting system runs once every 80 min for 10 seconds. Even with 3x 150W metal halogen lights on, the humidity in the top 1/3 of the viv does not drop below 70%.

In a smaller viv, you might see faster humidity dissipation - but it is certainly possible to have an open top and maintain frog-suitable humidity. Automated misting is critical for that, however.


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## serial hobbiest (Mar 5, 2017)

kimcmich said:


> @serial_hobbyist,
> 
> I have a large viv 5 feet x5 feet x2.5 feet with an open top. During the day, my misting system runs once every 80 min for 10 seconds. Even with 3x 150W metal halogen lights on, the humidity in the top 1/3 of the viv does not drop below 70%.
> 
> In a smaller viv, you might see faster humidity dissipation - but it is certainly possible to have an open top and maintain frog-suitable humidity. Automated misting is critical for that, however.


As I suspected. The timer in the MistKing beginner's kit that I have coming isn't capable of such a high frequency of misting- just 10 events daily, max. Living on Vancouver Island, as far as humidity control is concerned, I wouldn't need to mist at all _most of the time,_ as the average humidity here is 75%. That being said, it can dip below 25% on hot summer days, or during winter cold snaps when the temperature dips below freezing. So, I think I'll go with "mostly enclosed" configuration, so I'm not caught off- guard by those dry days.

Thanks again everyone.


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## Pumilo (Sep 4, 2010)

Personally, I think that is a wise decision. I feel something like that is best done after you've kept frogs for a year or 3.
More important, I believe that is the kind of thing where when you are ready for it, or close to ready, you wouldn't be asking if it were possible. You'd instead be asking for help on how to get around a particular detail, like the Mistking only doing 10 cycles a day, or what substrate would hold the most moisture while still being well drained. By the way, if your heart were set on trying this, homemade clay would be the substrate, and there may be a way around the 10 cycle limit, through the hydroponics industry. You could look into a humidity controller. You'd have to tie your MistKing into that, instead of the humidifier that the controller is designed for. Don't forget that the MistKing pump is only 24 volts without the adapter. It would require an adapter.
The down sides would be one more sensor you'd have to hide in your viv, and also, you are relying on technology to keep your frogs alive. If it fails to perform on an especially dry day, or there is a power outage while you are off visiting Auntie Gertrude, are your frogs safe? If I have a power outage, all I have to worry about is my vivarium's temperature.


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## Pumilo (Sep 4, 2010)

serial hobbiest said:


> Okay, thanks everyone. Glass it is.
> 
> With no forced air circulation, will a 1" screen at the top, plus the front vent in an Exo-Terra terrarium suffice for ventilation, should I ever end up with a pickier plant?
> 
> If I seal up my top so that it's un-openable, (or place the viv in a location where the top in rather inaccessible regardless), is there much concern of frogs jumping out the front door when I open it up to feed them? I only plan to get two D. tinctorius azureus.


Escape is more of a problem with smaller, faster frogs, like pumilio and thumbnails. It is wise to keep that in mind, and don't design the perfect hiding spot right where you open the viv to work and feed. Then it is a simple thing to make sure a frog doesn't get spooked and jump straight out when you open the door. If your clearing is frog free, it doesn't matter where they may be in hiding. You don't need to know where they are, just where they aren't.

On your other question, I'm unfamiliar with the Exo Terra vent, as I always scratch built, so I can't say for sure. I like to go with a full inch below the door, and a full inch above it. If you have less than that below the door, go with a 1.5" vent on top. As Ed pointed out, it's very easy to partially cover a vent. It's not always so easy to add more later. That makes for an easy answer. If the amount of ventilation is in question, go bigger.


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## serial hobbiest (Mar 5, 2017)

Pumilo said:


> On your other question, I'm unfamiliar with the Exo Terra vent, as I always scratch built, so I can't say for sure.


It's not much, just FYI. It's basically a series of slots less than 1/4" long. A 1/4" wide screen would provide better ventilation. For that matter, the tiny gap that runs along the hinged edge of the front doors probably provides similar ventilation.

So, I will refer to your useful stickied thread on how to build the mini screen, although I wont bother butchering the corner pieces, as I need to build it a little wider anyhow to compensate for the lack of ventilation in the front... On second thought, I'll guess I'll have to trim them a little bit, else be stuck with a minimum 2.5" screen, which seems a little large, being at the top & all. I'll shoot for your recommended 1.5".

Thanks again to you & Ed for all your useful help & advice. I'd be pretty lost without you guys, so I just want you to know it's very much appreciated.


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## Ed (Sep 19, 2004)

serial hobbiest said:


> As I suspected. The timer in the MistKing beginner's kit that I have coming isn't capable of such a high frequency of misting- just 10 events daily, max. Living on Vancouver Island, as far as humidity control is concerned, I wouldn't need to mist at all _most of the time,_ as the average humidity here is 75%. That being said, it can dip below 25% on hot summer days, or during winter cold snaps when the temperature dips below freezing. So, I think I'll go with "mostly enclosed" configuration, so I'm not caught off- guard by those dry days.


Keep in mind that you use a longer misting period to make up for the reduced exterior humidity. Where I live it can dip down to 25% humidity and I shut down the frogs last year by reducing the misting to once a day for approximately 15 seconds (and I have large 4 inch vents on the front of 20 gallon conversions) without any issues for the frogs.

some comments 

Ed


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