# Air Circulation in a Vivarium. Questions and comments



## grabberorangestang

Well hello everyone! I officially ordered my 18x18x18 Zoo Med terrarium today at the shop. It should be here this week. This is my first vivarium, and I am still planning it as I am in no hurry. I bought a 40mm computer fan that pushes almost 5cfpm of air. The zoo med has the euro vent on the front glass so I am wondering if I should use it as an exhaust fan to suck air from the top of the terrarium and push outwards (the new air coming through the euro vent). Would this cause a drastic drop in humidity? Would it be best to run it maybe twice a day after misting and thats it? Or should I run it the majority of the day/always inside the vivarium? This would slowly bring new air in through the crevices and euro vent, but it wouldn't be directly blowing out old air or sucking in new air. More or less recirculating the existing air. Please offer thoughts and comments. 

Also as a side note. I plan to manually mist twice a day. Whats the "right" amount. Does anyone have a good article to read? Most people set up mist kings, but this is my only setup and I enjoy tinkering around with stuff. Also I know some plants don't like water on their leaves, should you avoid misting them? Or does this mean to not always have water on the leaves. Thanks everyone you are a great help! I bought the foam, silicone, and egg crate today. Once I receive the tank it will be background sculpting time.


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## ajwoods88

In regards to your misting question, there's one thread that explains misting options for beginners that's quite helpful. 

Here's the link... 

Misting for Beginners


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## sarahspins

Sucking air out of the tank (or blowing room air in) is going to draw too much humidity out (just opening one of the doors can cause the humidity to drop a significant amount). You may not need extra (mechanical) ventilation depending on how you intend to change/modify the top. I have glass on the top of my exo terra with a 1.5" wide vent and it works really well at maintaining humidity while still allowing enough airflow that I don't worry about needing more (and like many I keep a strip of plexiglass handy to cover the vent if I need to). 

There are only two reasons I could see for needing to add any kind of ventilation or circulation, and the first is if you have any plants that require some air current to thrive. In that situation I'd lean towards running the fan inside the tank for short amounts of time throughout the day - but not constantly. The other is if you need some air flow to cool the tank down a few degrees, but that makes things more complicated since moisture needs to be replaced as it evaporates.


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## grabberorangestang

Thanks for the input and I appreciate the misting thread! It sounds to me that since I have a euro vent on the front, and will possibly drill a hole in the top to add some ventilation, I shouldn't need a fan for circulation. Opening the door daily will provide enough circulation on top of the vents so there isn't stagnant air. A fan would be helpful if the tank was too warm or particular plants needed it.


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## Dendro Dave

sarahspins said:


> Sucking air out of the tank (or blowing room air in) is going to draw too much humidity out (just opening one of the doors can cause the humidity to drop a significant amount). You may not need extra (mechanical) ventilation depending on how you intend to change/modify the top. I have glass on the top of my exo terra with a 1.5" wide vent and it works really well at maintaining humidity while still allowing enough airflow that I don't worry about needing more (and like many I keep a strip of plexiglass handy to cover the vent if I need to).
> 
> There are only two reasons I could see for needing to add any kind of ventilation or circulation, and the first is if you have any plants that require some air current to thrive. In that situation I'd lean towards running the fan inside the tank for short amounts of time throughout the day - but not constantly. The other is if you need some air flow to cool the tank down a few degrees, but that makes things more complicated since moisture needs to be replaced as it evaporates.



That isn't really true (IMO) if you set it up right with an interval timer and tune your setup so that on average the fan comes on just enough to keep the glass clear most of the time, especially if you have the fan blow over/across the vent instead of straight down into the viv, or sucking air out of the viv and blowing it into the room. 

Just set your fan to blow across the lid, either from one side, or front to back/back to front if the lights aren't in the way. Between intervals the humidity rapidly rebuilds, and if you've got it tuned right so you are just barely keeping your glass clear through the day, then the humidity never really drops to unacceptable levels...at least not for very long, and the frogs can handle 15 min of 50-70% humidity when they are sitting on a moist substrate and well hydrated, but hell I've seen frogs camp out right under the lights for fair periods of time...they don't mind a humidity drop much if they are well hydrated. Really the to methods when you factor everything in are about equal...except in viv fans are more hassle to setup/maintain, and any added benefit you do get is minimal, as long as your outta viv system is tuned decently. 

Also this is another time when micro climates could come into play. In regions like near the floor, back corners, around/under plant leaves/logs/rock where the frogs are likely to be, you'll have cooler/higher humidity micro climates that ease any hardship caused by a fan on for 15min once ever 1-3 hours (I find somewhere around that interval is where there is usually the balance between clear glass and high humidity)

In fact if you're using slightly raise lights you can kill 2 birds with one stone and use the fan to cool the lights and blow over the vent to keep your glass clear and that is usually enough air exchange for the frogs and plants, and the warm air from the lights gets to mixed up with the room air to do much harm if the fan blows it into the viv, and then the evaporative cooling going on in the viv and due to the air exchange mitigates any warm air from the lights even further...Now if you set it up so that it was pumping warm air from the lights directly into the viv through a duct or hose...then you'd have a problem. 

Inside the viv fans are great if you wanna go through the hassle, but not worth it to me unless it is a very large and/or tall tank where just a vent, or even a fan blowing across the vent may not be sufficient enough for some parts of the viv, especially the lower regions of glass. 

I'm not a fan of the frogs in sealed tanks old school wisdom...we know more now about frog and plants, and that they both, in fact the entire environment they are being kept in benefits from more air exchange then you get in a seal tank only lifting the lid to feed or mist. Creating the perfect conditions for most bacterial or fungal, maybe viral pathogens and that will likely exacerbate any health issues that do arise ....is not optimal. So sealed vivs, not the devil since we know plenty of people have kept and raise healthy frogs that way...*but not optimal.*


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## grabberorangestang

Dendro Dave said:


> That isn't really true (IMO) if you set it up right with an interval timer and tune your setup so that on average the fan comes on just enough to keep the glass clear most of the time, especially if you have the fan blow over/across the vent instead of straight down into the viv, or sucking air out of the viv and blowing it into the room.
> 
> Just set your fan to blow across the lid, either from one side, or front to back/back to front if the lights aren't in the way. Between intervals the humidity rapidly rebuilds, and if you've got it tuned right so you are just barely keeping your glass clear through the day, then the humidity never really drops to unacceptable levels...at least not for very long, and the frogs can handle 15 min of 50-70% humidity when they are sitting on a moist substrate and well hydrated, but hell I've seen frogs camp out right under the lights for fair periods of time...they don't mind a humidity drop much if they are well hydrated. Really the to methods when you factor everything in are about equal...except in viv fans are more hassle to setup/maintain, and any added benefit you do get is minimal, as long as your outta viv system is tuned decently.
> 
> Also this is another time when micro climates could come into play. In regions like near the floor, back corners, around/under plant leaves/logs/rock where the frogs are likely to be, you'll have cooler/higher humidity micro climates that ease any hardship caused by a fan on for 15min once ever 1-3 hours (I find somewhere around that interval is where there is usually the balance between clear glass and high humidity)
> 
> In fact if you're using slightly raise lights you can kill 2 birds with one stone and use the fan to cool the lights and blow over the vent to keep your glass clear and that is usually enough air exchange for the frogs and plants, and the warm air from the lights gets to mixed up with the room air to do much harm if the fan blows it into the viv, and then the evaporative cooling going on in the viv and due to the air exchange mitigates any warm air from the lights even further...Now if you set it up so that it was pumping warm air from the lights directly into the viv through a duct or hose...then you'd have a problem.
> 
> Inside the viv fans are great if you wanna go through the hassle, but not worth it to me unless it is a very large and/or tall tank where just a vent, or even a fan blowing across the vent may not be sufficient enough for some parts of the viv, especially the lower regions of glass.
> 
> I'm not a fan of the frogs in sealed tanks old school wisdom...we know more now about frog and plants, and that they both, in fact the entire environment they are being kept in benefits from more air exchange then you get in a seal tank only lifting the lid to feed or mist. Creating the perfect conditions for most bacterial or fungal, maybe viral pathogens and that will likely exacerbate any health issues that do arise ....is not optimal. So sealed vivs, not the devil since we know plenty of people have kept and raise healthy frogs that way...*but not optimal.*


Thank you for your input, although I am a little confused on how you recommend setting up the fan. Do you have a glass top? Is the fan half in the tank half outside? I would plan for it to blow from back to front to help clear the front glass and use the euro vent. Thanks


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## Dendro Dave

grabberorangestang said:


> Thank you for your input, although I am a little confused on how you recommend setting up the fan. Do you have a glass top? Is the fan half in the tank half outside? I would plan for it to blow from back to front to help clear the front glass and use the euro vent. Thanks


This guy has a pic in his post that shows what I was talking about, though I tend to just mount the fan so it blows from one side to another, instead of front to back, or back to front since my lights are normally in the way.
http://www.dendroboard.com/forum/pa...-how-do-you-mount-your-fan-3.html#post1395353 (<--Link should take you right to the guys post where he shows the fans just sitting on top)
That thread may be worth reading for you if you haven't already.

It is really simple though, just make it so the fan blows across the viv top instead of blowing straight into the viv. Most people's normal inclination with an outside viv is to have it like face down on top of the vent blowing into the viv, or face up on the vent sucking air out of the viv and blowing it into the room. That way can work if you are careful not to run the fan to much and have your timer well tuned...but just having a fan blowing across the top surface of the glass top and vent is enough usually and much more margin of error in case your interval choice was to frequent.

And this thread shows how I make my vents...
http://www.dendroboard.com/forum/pa...c-filter-foam-fans-vents-ff-lids-etc-etc.html


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## grabberorangestang

Much Appreciated!


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