# How To Ventilate



## connorology (Oct 6, 2018)

Good Morning, 

So I just finished setting up a terrarium with one of my roommates. The plan is we will eventually stock it with frogs (probably P. terribilis) but that's a couple months away, we want to let it grow in first. The basic layout should be linked above. 

My question is this: what do we need to do for ventilation? I have seen a bit of contradictory information regarding this particular husbandry element. This is a planted aquarium, so the airflow will be worse than in the made-for-herps terrariums on the market. As of now, we don't have much ventilation except for an eight inch gap up top that's probably about an eighth of an inch wide. 

I was planning to drill a few more holes into the plastic top to make sure there's more gas exchange with the outside. Alternatively, we are technically capable of installing a computer fan in the top to vent the whole thing, but I would prefer not to do that unless absolutely necessary, because it's more time and resources. I'd like to hear some thoughts about the ventilation situation. How do folks tend to vent their enclosures?


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## gonzalez (Mar 28, 2018)

Personally I just make vents out of window screens which I have running across the front of the lid. You could drill holes and put screen on it for passive ventilation, I don't think computer fans are necessary.

Sent from my SAMSUNG-SM-G920A using Tapatalk


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## S2G (Jul 5, 2016)

All I use are aquariums. What I do is drill as many holes as possible in the plastic piece that comes with versa all glass tops then silicone no seeum type screen. On a 20L to 29g this is good enough with a fan blowing over the vent on intervals to keep humidity where I want it

The problem starts at 40B+. This is tricky and can be a little nerve racking at first. I'll drill 2 50mm holes right behind the plastic piece then a hole in the back with a fan pulling out on intervals or I'll do the same except drill 50mm holes on the back then run an internal fan.

Easiest route is venting the plastic piece then drill holes behind that then run an internal fans.

Make a template out of scrap wood then run water over it. Don't put pressure on your drill the weight from the drill is enough. Drilling glass is very easy


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## connorology (Oct 6, 2018)

gonzalez said:


> Personally I just make vents out of window screens which I have running across the front of the lid. You could drill holes and put screen on it for passive ventilation, I don't think computer fans are necessary.


Do you do that for aquariums? That would probably be my preference, I don't want to much about with additional electronics if I don't have to. The humidity stays super high right now, but even without an additional vent it looks like the tillandsia are drying off ok. 



S2G said:


> All I use are aquariums. What I do is drill as many holes as possible in the plastic piece that comes with versa all glass tops then silicone no seeum type screen. On a 20L to 29g this is good enough with a fan blowing over the vent on intervals to keep humidity where I want it
> 
> The problem starts at 40B+.


What is 40B+? 40 gallons? Our terrarium is 44 gallons I believe, so it is fairly large. Do you think we are in trouble without a fan?


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## MasterOogway (Mar 22, 2011)

This.

And honestly, you don't even need to use screws to secure it down, just a few dabs of silicone will do. It's super easy, customizable to the width you need, and easy to do. No drilling of glass or plexi required here. Did I mention it was easy?


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## S2G (Jul 5, 2016)

connorology said:


> Do you do that for aquariums? That would probably be my preference, I don't want to much about with additional electronics if I don't have to. The humidity stays super high right now, but even without an additional vent it looks like the tillandsia are drying off ok.
> 
> 
> 
> What is 40B+? 40 gallons? Our terrarium is 44 gallons I believe, so it is fairly large. Do you think we are in trouble without a fan?


40 breeder

I don't think you'll be in trouble, but I believe it would benefit everything inside to have one. It will be stuffy in there without at least a fan over your vent.

What I'm doing on the newest builds are drilling holes on the sides right above the substrate then using vents in the back. Basically replicating the exo terra design. 

I'll say this. I've regretted not putting a fan in, but I've never regretted putting one in.


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## Socratic Monologue (Apr 7, 2018)

connorology said:


> What is 40B+? 40 gallons? Our terrarium is 44 gallons I believe, so it is fairly large. Do you think we are in trouble without a fan?


I have a 15 gallon high tank (tall, like yours looks) used as a viv, with a full screen top, no fan. Even with all that vent on top, the bottom gets kind of funky. I intend to rebuild it and drill low vents into the sides at some point, only because the shelf it is on won't fit an Exo Terra, which is way easier to tweak the ventilation on.


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## connorology (Oct 6, 2018)

S2G said:


> I'll say this. I've regretted not putting a fan in, but I've never regretted putting one in.


Good to know, I'll keep it in mind, thanks. For a ~45 gallon aquarium, what size fan would get reasonable air flow? As in, if I decide to mount a fan in a vent, what type of fan should I get? And I assume it should be rigged up to blow air out instead of in?


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## connorology (Oct 6, 2018)

Socratic Monologue said:


> I have a 15 gallon high tank (tall, like yours looks) used as a viv, with a full screen top, no fan. Even with all that vent on top, the bottom gets kind of funky.


What do you mean by funky? Any plants or animals die?


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## jgragg (Nov 23, 2009)

> What I'm doing on the newest builds are drilling holes on the sides right above the substrate then using vents in the back. Basically replicating the exo terra design.





> I have a 15 gallon high tank (tall, like yours looks) used as a viv, with a full screen top, no fan. Even with all that vent on top, the bottom gets kind of funky.


I'm experiencing a bit of the same thing with a pair of 36" tall Exos with large areas of pond/stream - the lower glass fogs for much of the 24-hr day (all but the late afternoon). I'm strongly considering drilling some side vents to suck in fresh air. Plants down there are happy, animals can move wherever they like (it's relatively hot/dry up top by the lights, and chilly/damp at the bottom). It only seems to bother the operator, but hey, _that's me_! Ha ha ha.

This is the first time ever this has happened to me. These 36" talls are the biggest - by far - off-the-shelf vivs I've done. I've done bigger customs, and I always put in side vents way down low.



> I'll say this. I've regretted not putting a fan in, but I've never regretted putting one in.


@OP - I'm dead certain this is S2G's truth. He's in Alabama, a fairly humid area, even with air conditioning. I like in a desert, and enjoy a fan-free life. With chapstick! Ha ha. I think you'd be quite content with a fan, but I'm not certain you need one. I do advise improving your passive ventilation first, if you can swing the side vents down by the substrate. Then re-assess your need for active ventilation. In general, I think things that work well without active effort, are preferable to things that require active effort to get the same result. But - to each their own.

good luck!


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## Socratic Monologue (Apr 7, 2018)

connorology said:


> What do you mean by funky? Any plants or animals die?


'Funky' like armpits in the rainforest -- the substrate doesn't dry, the glass grows a beard, cats and dogs living together...well, it isn't that bad, but it isn't possible to open up some vent or other and dry the bottom of the tank out. Sometimes my Exo Terras will get too moist for too long, but in those I can expose some more screen on the top for a day or two; at the bottom of a top-opening viv, there aren't any passive vent options down at the bottom. I suppose I could install a fan up top blowing down pretty easily, but passive ventilation is much easier to dial in, I think. Plus, then the top would dry out too much, probably.


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## S2G (Jul 5, 2016)

jgragg said:


> I
> 
> @OP - I'm dead certain this is S2G's truth. He's in Alabama, a fairly humid area, even with air conditioning. I like in a desert, and enjoy a fan-free life. With chapstick! Ha ha. I think you'd be quite content with a fan, but I'm not certain you need one. I do advise improving your passive ventilation first, if you can swing the side vents down by the substrate. Then re-assess your need for active ventilation. In general, I think things that work well without active effort, are preferable to things that require active effort to get the same result. But - to each their own.
> 
> good luck!


Theres so many variables its really hard to help someone nail it down. Its 60% in my basement right now. That will just affect you interval times and misting really. 

I will say you need at least a fan on top blowing over your vent with a non drilled aquarium., but it still gets stuffy on 29s during the summer with higher misting.

An 18" wide tank with just a vent in the front top is extremely humid. I'm drilling more vents in the top this weekend. (2) 52mm right behind the front vent then 2 in the back for a circ fan.

The new 40b I'm going to drill holes in the sides right above the substrate then some in the top back along with the front vented plastic piece. This has worked extremely well on a 10g I used to try it out on.

Can you tell I'm not a fan of exo's?


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## S2G (Jul 5, 2016)

connorology said:


> Good to know, I'll keep it in mind, thanks. For a ~45 gallon aquarium, what size fan would get reasonable air flow? As in, if I decide to mount a fan in a vent, what type of fan should I get? And I assume it should be rigged up to blow air out instead of in?


Your going to have dial this in on intervals to get your humidity level you want. I use a 90mm affinity muffin fan with a dimmer so I can throttle the fan speed back. You don't want it to come on at 100% , but a slower speed over a period of time. 

Can you give me (us) some more details.
* what's your humidity in the room this is going in?
* are you using a versa or std aquarium glass lid?
* how do you feel about drilling glass or do you have the tools necessary?
* any orchids, air plants, aquatic moss?
* what type of frogs? I'm assuming a group terrestrial type
* false eggcrate bottom or clay balls?
* is this a tight budget build?

I've just been taking a stab at it, but this will help truly narrow it down to something that will work for you.


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## connorology (Oct 6, 2018)

Yeah thanks for all the suggestions it's much appreciated. More details: 

1. The room it's in right now is fairly dry, probably 40% humidity. I am in Northern California, so it's not a desert, but for large chunks of the year it might as well be. 

2. The lid we have is hard to describe as it's custom-ish, but for the purpose of this discussion it's acrylic. Easy to punch holes in.

3. I have glass drilling tools accessible, but I'd prefer not to punch any more into the aquarium unless absolutely necessary. 

4. As for plants, there aren't any orchids. It's peperomia, ferns, creeping fig, and a tiny ficus on the ground level, and then bromeliads higher up. I have some tillandsia adhered high up in the tank and I think they'll be ok, but if they're not it's not the end of the world. They were sort of "mine canary" plants to see if I could maybe add an orchid later. 

5. In terms of animals, we haven't stocked it yet. The plan is terribilis, but honestly we may just wait to see what temps and humidity is easiest to maintain and choose based on that. 

6. It's a plastic false bottom from egg crate, no clay balls. 

7. Budget - we're veterinary students, so this was originally intended as a budget build, but we sort of went crazy with it. 

I'll post pictures of this later when I am home. 

Actually since the last post we went slightly crazy with the high-tech ad ons and bought a fan and a humidity/temperature probe that can automate the fan and a humidifier if the parameters drop out of an acceptable range. So current plan is to install that in the top and see if we're getting sufficient decreases in temp/humidity (right now with all the LED lights on and completely closed it can get up to 84f and 99% humidity, though that drops if we keep the top cracked). 

Do you think it's smarter to try and circulate drier air into the tank to promote evaporation, or to pull warm humid air out of the tank (ie, should the fan point in or out).


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## kimcmich (Jan 17, 2016)

> Do you think it's smarter to try and circulate drier air into the tank to promote evaporation, or to pull warm humid air out of the tank (ie, should the fan point in or out).


 Moving air has lower pressure than the air around it - so creating an air current in the viv that passes near the vents will automatically pull in air from outside the viv. This phenomena is convenient since venting directly from outside the viv might be too desiccating in the area immediately in front of the vent.

Placing a fan so that it blows past the vent hole(s) would be a good place to start. The closer the fan is to the holes, the stronger the pull from outside will be.


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## jgragg (Nov 23, 2009)

> in Northern California


More like Eureka or more like Bishop? Yreka or Truckee? Big area, many many climates. But you said vet school, which narrows it down to...Davis, yes?

I lived way up on the NorCal coast about 12 years, it was Great! for keeping humid-viv herps. Nice nocturnal cool-down, always nice and humid, no risk of cooking your animals in a heat wave, little risk of freezing your animals in a winter power outage. A little gentle heating, and lighting of course, was all that was needed.

Davis gets pretty warm - but stays fairly humid, right? - in summer, and is pretty chilly/clammy in the winter. Almost frost-free. I'd think it a pretty easy area to go quite passive, on environmental control. I think the hygrometer/humidifier purchase was probably not necessary. But if you're into that, hey, do as you will, and do it well.



> 3. I have glass drilling tools accessible, but I'd prefer not to punch any more into the aquarium unless absolutely necessary.


Is this a viv or an aquarium? It's a viv, right? Don't be afraid to do what you need to it. I say drill some vent holes down by the substrate. If you ever deploy it to fish again, hey, silicone and glass are cheap. It's an easy patch. Those vents, and if you determine you need, some light fan action across the top, should eliminate your zone of funk. The vents will also allow CO2 to passively drain out the sides. Organic substrates, kept moist, will produce this...just something to chew on.

Your plants are mostly pretty tough. The tillies seem like the only iffy ones. There are some tough orchids out there, if you find a vacant niche. They aren't all fainting ladies, by any means.

Good luck!



> Can you tell I'm not a fan of exo's?


Oh, _I hear you_. They are barely adequate in terms of function, generally needing some mods, and for what you get the price is pretty obscene. I used to be strictly DIY on my viv hulls. As life has progressed I find myself with more money than time, however. The ease of dropping a few bills at my local Expo or shop outweighs any DIY initiative I have left. Ditto staying current on who's still in business, building what, with a decent rep for standing behind their product. Plus dealing with UPS or whoever when things arrive broken? Ah jeez. Total PITA. Thus, off-the-shelf Exos are more of a go-to solution these days. When I retire I am dead certain it will be DIY all over again. Or maybe someone by then will have developed a better product line.


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## connorology (Oct 6, 2018)

Yes, I am in Davis. I've got some pictures of the general setup I will include below. We added all the plants on Friday so we'll see what takes and what doesn't. I'm expecting some die off from the creeping fig, and the purple heart cutting up top is looking a little questionable, but I have some replacements available in case anything doesn't take. I have some moss mix coming in the mail too, so I am hoping I can get some moss growth. 





































Then this is the current incarnation of the top: 










The Fan: 










The LEDs










Right now we have the fan pointed in and we are going to let it run for a few hours to see what it equilibrates to. We can switch it to pointing out if we're not getting the effects we want, and we can experiment with other vents as well. The main reason we don't want to drill the glass is because there's the chance of failure, but also the chance we'll just make it look junky.


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## jgragg (Nov 23, 2009)

Oh, that's lovely. Thanks for sharing.

It'll be a cryin' shame when that creeping fig smothers everything! 

Ha ha, kidding/not kidding. I think you'll come to regret its presence. Unless of course you're the type who enjoys pruning. If you're unwilling to kill it now I advise taking a picture of the tank in a condition when you're happy with the fig coverage, and then trim hard to that standard at frequent, regular intervals. Otherwise you're at risk of a shifting baseline, and a creeping horror.

One idea, if you must harbor it - keep it epiphytic, do not let it utilize the deep substrate or the drainage layer.

good luck!


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## connorology (Oct 6, 2018)

jgragg said:


> Oh, that's lovely. Thanks for sharing.
> 
> It'll be a cryin' shame when that creeping fig smothers everything!
> 
> Ha ha, kidding/not kidding. I think you'll come to regret its presence. Unless of course you're the type who enjoys pruning.


I think it'll be fine, I'll just hack it back when it gets overgrown. I've got schefflera trees in my chameleon's vivarium and I basically need to cut 6-8 inches out every other week, so I'm used to it.


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## jgragg (Nov 23, 2009)

> I think it'll be fine, I'll just hack it back when it gets overgrown.


Yeah, you're probably right.

Keep the hackers handy for that _Tradescantia_ too....same idea - don't let it access the terrestrial & subterranean resources. Force it to "epi".

Good luck!


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