When is just top ventilation good enough?

[Vulash]

There are some decent glass enclosures out there that only have top ventilation. When do you find these acceptable to use? I know folks use Exo Terra tall for some arboreals. What else do you use?

I rather like the Zoo Med "Creature Den" and recently picked up a Thrive Reptile Terrarium fairly cheap. Both of those have tops that aren't overlapped mesh, so they don't require modification in that regard. There is no cross-ventilation, however. (By "rather like" I mean the look, quality, dimensions, etc - not as in "I use them for all Ts). I've seen threads with discussions about the Reptizoo glass vertical enclosure that is good for fossorials.

I also recently picked up a cheap 2.5 gallon glass aquarium for experimentation. I attempted to drill some ventilation with a bit designed for glass. The issue is that the glass isn't very well supported in a pre-built enclosure like that. The glass broke in 2 out of 4 holes. There is no way I could confidently get enough holes for full ventilation without ruining the whole thing.

So again, when do you use these? Drier climate terrestrials? A GBB?

And knowing how much Avic and related Ts need cross-ventilation, when do folks decide it's okay to switch to Exo Terra? Once they reach adulthood?

These questions are more general, but I guess I'm wanting to understand the nuance of glass enclosures a bit more. So far, I'm not a huge fan of acrylic.

 

[Wolf135]

From what I've heard its ok with dry climate Ts.

 

[Wolfram1]

You can use them BUT there is much less room for error when it comes to balancing the ventilation with moisture in the soil. So it really comes down to experience, every tank is different, substrate, decor and especially every lid/ventilation is different, often the lids are "homebrewed" i use wooden lids for example, and every Theraphosidae species has different requirements, so there is really no guide to follow.
Its sink or swim basically, which is why i would not reccomend my setups to anyone even if i personally prefer them to the front opening, "better"-ventilated terrariums.

 

[Dorifto]

I also recently picked up a cheap 2.5 gallon glass aquarium for experimentation. I attempted to drill some ventilation with a bit designed for glass. The issue is that the glass isn't very well supported in a pre-built enclosure like that. The glass broke in 2 out of 4 holes. There is no way I could confidently get enough holes for full ventilation without ruining the whole thing.

Do this. Slow but steady. Then use a L shaped profile and another plastic, acrylic, glass support from a desired size. This will allow a great air flow.



Then add another grille on top on the lid, or like this design two glass panels and some acrylic hinges, and the grille sandwiched in between.

So again, when do you use these? Drier climate terrestrials? A GBB?

Plot twist, GBBs are pretty humid species.

Only the soil it's very dry (xeric). Simply because doesn't rain it doesn't automatically mean that the climate is dry. They have a very humid climate as they are surrounded by warm water (Paraguaná peninsula) but it doesn't rain (very rarely or very low amount) so the soil it's quite dry (xeric).

@wolfram explained you quite well the restrictions of the top only vented enclosures. But I'd add that the size of the open area (grille/mesh) affets a lot to the amount of ventilation they receive.

 

[Wolfram1]

Something worth mentioning is also that moss playes a critical-role in letting water evaporate quicker, it is not just a decoration. In enclosures that lack a chimney-effect or cross ventilation you need to be very careful not to overdo it.

 

[AphonopelmaTX]

I don't know where the idea that arboreal tarantulas, or Avicularia spp. specifically, need cross ventilation came from, but it is completely false. Any tarantula can be housed just fine with the ventilation at the top of an enclosure so long there is enough to allow it to dry out. With the arboreal tarantulas, including the Avicularia spp., sometimes placing ventilation on one of the sides of the enclosure is just more convenient because the lid of most pet store bought containers- glass aquariums or Kritter Keepers for example- have a door or other means of access which can be used when standing the container on end. For example, using a glass aquarium stood on end to where it is taller than long and using a screen lid on the front (which would be the top when oriented horizontally) provides for perfectly suitable ventilation without the need to drill additional holes in the glass.

 

[Vulash]

There is a lot to unpack here but thank you all for the discussion. I learn best by understanding "how" or "why" a thing is instead of just "the consensus of experienced keepers is to do this thing for this species, so I'm doing that thing". With Ts it allows me to make logical steps for other species or conditions as well. That's why I appreciate conversations like this. Okay to the unpacking.

Do this. Slow but steady. Then use a L shaped profile and another plastic, acrylic, glass support from a desired size. This will allow a great air flow.

View attachment 430019

Then add another grille on top on the lid, or like this design two glass panels and some acrylic hinges, and the grille sandwiched in between.



Plot twist, GBBs are pretty humid species.

Only the soil it's very dry (xeric). Simply because doesn't rain it doesn't automatically mean that the climate is dry. They have a very humid climate as they are surrounded by warm water (Paraguaná peninsula) but it doesn't rain (very rarely or very low amount) so the soil it's quite dry (xeric).

@wolfram explained you quite well the restrictions of the top only vented enclosures. But I'd add that the size of the open area (grille/mesh) affets a lot to the amount of ventilation they receive.

I like the design here, but if I'm understanding this, I would still be drilling holes in the front bottom. Is that correct? Maybe it was because I used a cheap $15 2.5 gallon, but I was going slow and steady and still had cracking. I tried multiple RPMS of the bit and lubrications. It's a carbide tipped spade bit (meant for glass), are you using a diamond bit? At the time, I was hoping to make smaller holes and the diamond bit doesn't come in 1/8" as far as I know. I believe the issues is just lack of support for the glass front in a cube.

I don't know where the idea that arboreal tarantulas, or Avicularia spp. specifically, need cross ventilation came from, but it is completely false. Any tarantula can be housed just fine with the ventilation at the top of an enclosure so long there is enough to allow it to dry out. With the arboreal tarantulas, including the Avicularia spp., sometimes placing ventilation on one of the sides of the enclosure is just more convenient because the lid of most pet store bought containers- glass aquariums or Kritter Keepers for example- have a door or other means of access which can be used when standing the container on end. For example, using a glass aquarium stood on end to where it is taller than long and using a screen lid on the front (which would be the top when oriented horizontally) provides for perfectly suitable ventilation without the need to drill additional holes in the glass.

The idea is so prevalent that I was certainly convinced. I think even here we see references to needing cross-ventilation as a priority. Now obviously it's not conveyed as required since people do use glass enclosures for adult Avicularia spp. (and similar).

I don't want to overquote here since there were many good responses. Let me explain the ultimate goal of this question.

The first was I just moved my GBB to a glass enclosure. It has a metal screen top, but not the type that will cause a T to get stuck, and I believe too strong for them to chew through. But that means it has a LOT of top ventilation. What I've done is put my "french drain" in one corner so that I have direct access to the bottom with water. I have sphagnum moss in the very bottom layer. My expectation is I can keep the bottom layer of substrate moist while allowing the top layer to remain nice and dry for my girl. I also have a water dish on each side of the enclosure. A small one near her for drinking, and a larger and deeper one near the pebbles.

If things dry out too fast it's easy to add packing tape on part of the ventilation, with the sticky side facing out. I see folks talk about some enclosures venting too quickly, but I never see mention of just covering a percentage of the ventilation area.

The second reason I'm asking is for planning into the future. There are many posts and podcasts on enclosures, but most seem to focus on slings, smaller adults, or arboreal species. I have a few "giants" growing (not Theraphosa spp.). Assuming at least a few of those will hit 9 inches, I'm going to need an enclosure that is 24"+. I'm not interested in opaque Sterilite or similar containers. I'll want to display most of my Ts, if not all. I have yet to see an acrylic enclosure that large, and honestly from what I've experienced with acrylic so far, I wouldn't want one that size unless I make it myself. That leaves glass. I should probably make a separate question on this topic, but I wanted to give the reasoning for planning ahead with glass.

I'll add a picture of my current GBB enclosure from my phone under this post. I want to give this caveat here, however. Some folks here won't like what I've done. I'm attempting to make a cool fantasy scene where my GBB slowly webs over the "heros" and makes cool tunnels and such around various pieces of curved wood. I don't normally add as much decoration (usually none) as I have in this case, and the enclosure is big for the GBB. So, this is an exception to how I normally do an enclosure, and it's for my own benefit. I believe I've mitigated as much risk as I can. This GBB has never climbed high up in their previous enclosure (or this one). Even then, my fall height should be fine, and I've set the one really hard item (the castle) up in a way that there is very little room for the GBB to fall on it. I'm also very careful with feeders and my GBB has no issue feeding.

I'm still happy to receive critical feedback, but those are my reasonings for making this enclosure an exception.

 

[Vulash]

Here is the enclosure.

 

[Dorifto]

I like the design here, but if I'm understanding this, I would still be drilling holes in the front bottom. Is that correct? Maybe it was because I used a cheap $15 2.5 gallon, but I was going slow and steady and still had cracking. I tried multiple RPMS of the bit and lubrications. It's a carbide tipped spade bit (meant for glass), are you using a diamond bit? At the time, I was hoping to make smaller holes and the diamond bit doesn't come in 1/8" as far as I know. I believe the issues is just lack of support for the glass front in a cube.

Nah, don't use spade bits, more prone to cracking the glass if they hit any burr.

I always use round ones, they will make a perfect circle every single time. Just keep the area moist and drill without applying too much force.

Like these:



I'd recomend you yo use a guide, so the drill bit wont jump, slide etc. You can make one using a hard plastic. I used a broken glass to make one xD.

To keep it moist just use a spray bottle or using some playdoh make a dougnut/donut and fill it with water, so it always stays wet.

Sliding door lock tutorial

Hi guys, recently I have installed some integrated door locks into my enclosure sliding doors, since my little daughter is amazed with the Ts, and she want to kiss them... 😅 So let's go! Tools: Variable speed drill, not a must, but it will help a lot. Round glass bit. A flat surface to...

arachnoboards.com

 

[Vulash]

Nah, don't use spade bits, more prone to cracking the glass if they hit any burr.

I always use round ones, they will make a perfect circle every single time. Just keep the area moist and drill without applying too much force.

Like these:

View attachment 430105

I'd recomend you yo use a guide, so the drill bit wont jump, slide etc. You can make one using a hard plastic. I used a broken glass to make one xD.

To keep it moist just use a spray bottle or using some playdoh make a dougnut/donut and fill it with water, so it always stays wet.

Sliding door lock tutorial

Hi guys, recently I have installed some integrated door locks into my enclosure sliding doors, since my little daughter is amazed with the Ts, and she want to kiss them... 😅 So let's go! Tools: Variable speed drill, not a must, but it will help a lot. Round glass bit. A flat surface to...

arachnoboards.com

Thank you! I was using modeling clay and water as described, but the spade bit. I'm also using a drill press, so I don't think I'll need a guide. It sounds like the bit was my issue. I considered trying one of the style you listed but didn't want to sink more money in if it was a lost cause.

What bit speed do you use?

I'm going to give this another go. Luckily I still have my cracked test aquarium with two faces that aren't cracked yet lol.

 

[Wolfram1]

Hey,
while its certainly not my cup of tee to add any kind of decorations, unless they add to a more natural look, it should be funktional for now and

If things dry out too fast it's easy to add packing tape on part of the ventilation, with the sticky side facing out. I see folks talk about some enclosures venting too quickly, but I never see mention of just covering a percentage of the ventilation area.

that is a viable option should you need it. The fact that you mention noticing things drying too quickly or (i imagine this includes the opposite) beeing too humid is a good sign that you will hopefully be able to adjust the enclosure on the fly if anything is amiss.
You certainly can get away without any additional ventilation holes in this case.

 

[Vulash]

Do this. Slow but steady. Then use a L shaped profile and another plastic, acrylic, glass support from a desired size. This will allow a great air flow.

View attachment 430019

Then add another grille on top on the lid, or like this design two glass panels and some acrylic hinges, and the grille sandwiched in between.



Plot twist, GBBs are pretty humid species.

Only the soil it's very dry (xeric). Simply because doesn't rain it doesn't automatically mean that the climate is dry. They have a very humid climate as they are surrounded by warm water (Paraguaná peninsula) but it doesn't rain (very rarely or very low amount) so the soil it's quite dry (xeric).

@wolfram explained you quite well the restrictions of the top only vented enclosures. But I'd add that the size of the open area (grille/mesh) affets a lot to the amount of ventilation they receive.

Two more questions because I might attempt this soon. I have the new bits.

I assume the substrate can only come up to a depth of the horizontal "shelf" of your vent grilled. That would also mean you just leave that vent grill section exposed at the front of the tank?

Why not just drill the holes in the glass (the ones you've drawn on the vertical surface) just above the substrate level for the same affect? The only difference I can see if that you can drill larger holes the way you have it, and the glass might be more supported on that bottom edge.

 

[Dorifto]

I assume the substrate can only come up to a depth of the horizontal "shelf" of your vent grilled. That would also mean you just leave that vent grill section exposed at the front of the tank?

Correct, just fill the substrate right to the grille level. This way air enters just above the substrate level, taking moisture and keeping it humid and stable.

Like here:

IMG_20211005_163533.jpg

• Dorifto
• Oct 18, 2021
• 2

Acanthoscurria geniculata

Make sure that you give it a nice depth from the start, if not you can play with slopes etc.

Why not just drill the holes in the glass (the ones you've drawn on the vertical surface) just above the substrate level for the same affect? The only difference I can see if that you can drill larger holes the way you have it, and the glass might be more supported on that bottom edge.

One because if there is any air current nearby it will create a ram efect, forcing the air upwards. So it's more efficient and provides better gradients. Also it solves the fogging issue you could encounter with humid setups automatically. Other secondary but very important reason it's that it deters them from climbing the front glass. Being the air current homogeneus and vertical, it prevents them from climbing the glass for possible scaping points, since the only air current they feel comes from the bottom.

And two for aesthetics, because you have a clear view of the entire setup, without anything blocking the sight.