HCA: Hermit Crab Association

I have a 20 gallon tank for my hermit crabs and a wire cover. I cover most of the wire mesh with clear wrap so it keeps the humidity in and I have a reptile lamp heater on the other side of the wire mesh. Still, the temp and humidity only get up to about 72% for both. I read somewhere here that a glass top might be better? I found glass aquarium tops at our local pet stores but is there ventilation in those? If I hang the heater above the glass, will it crack the glass?

I think the reason your humidity is down is not because of your lid but your lamp. Heat lamps are known to zap humidity out of tanks and are not recommended. Instead, people will buy UTH ( under the tank heater) and put them on the side of the tank above the substrate line(not the bottom)

Sealing the tank up is always better to maintain humidity. I run a 150W moonglo bulb 24 hours a day, a large UTH on the opposite end of the tank, and two large bubbler pools. This combination keeps my humidity around 80-90% and temp around 72-85 depending on which part of the tank you measure.

I had an under the tank heater but it barely heated the tank up.....however, it was a hermit crab one on a 10 gallon tank at the time. It just never brought the heat up....maybe it wasn't strong enough? I also saw something where someone put a wet sea sponge under the middle of the substrate in the center and kept the under the heater pad on the bottom of the tank under where the sponge is located. Thoughts?

dalbani wrote: ↑

Sat Oct 03, 2020 10:05 pm

I had an under the tank heater but it barely heated the tank up.....however, it was a hermit crab one on a 10 gallon tank at the time. It just never brought the heat up....maybe it wasn't strong enough? I also saw something where someone put a wet sea sponge under the middle of the substrate in the center and kept the under the heater pad on the bottom of the tank under where the sponge is located. Thoughts?

Yep, probably needed a larger UTH. The sponge is not a reliable method. The most reliable is a bubbler pool. I use them for both fresh and saltwater myself.

What would you suggest is a good wattage for an under the tank heater? I just looked it up and the little one I had previously purchased was 4 watts. I found another that is 8 watts.... I wonder if there are other ones that are higher....hmm.....also, if I could only fit one bubbler in, would you suggest salt or freshwater? Thanks so much

dalbani wrote:What would you suggest is a good wattage for an under the tank heater? I just looked it up and the little one I had previously purchased was 4 watts. I found another that is 8 watts.... I wonder if there are other ones that are higher....hmm.....also, if I could only fit one bubbler in, would you suggest salt or freshwater? Thanks so much

Hi!

Ultratherm is the best uth. Don't go by wattage with these, just get the biggest one you can that will fit the back part of your tank above the substrate line. They have no adhesive, so you can attach them with duct tape. I just bought a 6"x47" on reptilebasics.com for $30+ship. You can then insulate them (so your uth doesn't work as hard), by using aluminum foil attached to cardboard on top of the uth (shiny side of aluminum on the uth, and cardboard facing out). My house isn't that cold, heat is kept on 72/73F, so I skipped the cardboard and just insulated with aluminum foil duct taped over the uth. You'll also want to buy a thermostat with this, so that the uth doesn't overheat your tank:

https://www.reptilebasics.com/ultratherm-heat-pads

https://smile.amazon.com/Century-Thermo ... e5a37a4fcf

I'd also recommend a glass cover. I use glass tops on my 20 gal iso and my 55 gal and I never have a problem with humidity. With my uth on, the humidity in my tanks is 95-99% all of the time. Your crabs will get air exchange when you open the lid every day to do tank maintenance.

Everyone has their own preference, but I personally don't use heat lamps with my tanks. A glass lid that completely seals the top, and sand/ee moistened to sand castle consistency works great for my humidity.

For a glass top, measure your tank, and search online under aquarium tops. That's how I found tops for both of my tanks. Here is a top for a 20 gal L :

https://www.amazon.com/H2Pro-Canopy-Gal ... B07GC9BM8L

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I already have the heater so if I wanted to try and hang it over the glass (maybe 6 inches or so above it), do you think it would possibly damage the glass or be a fire hazard?

Also, I assume if I do the under the tank heater on the back side, I can’t put a decorative background on the tank, right?

dalbani wrote:I already have the heater so if I wanted to try and hang it over the glass (maybe 6 inches or so above it), do you think it would possibly damage the glass or be a fire hazard?

If you have a uth that sticks to the glass, you cannot remove and reuse it. You also cannot insulate those, or other uth's that have padding on them. The only way a uth will work properly is if it is attached to the glass above the substrate line. The goal is to heat the air in the tank. I think putting a uth not on the tank won't do any good, as it will heat the air beneath it and not the tank air. I'm ocd about fires anyway, so hanging it like that would make me paranoid lol.

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dalbani wrote:Also, I assume if I do the under the tank heater on the back side, I can’t put a decorative background on the tank, right?

You could probably put the background on the tank on the inside if you wanted to. But I def wouldn't put it on the outside of the tank and the uth on top of that.

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I would also still get a thermostat with whatever uth you have. It allows you to set a specific temp (say 80°F), and the uth will click off once it gets that warm. If you don't have a thermostat you have to be careful that the uth doesn't get too hot for the crabbies.

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No not the Uth to hand but the reptile bulb I have. I was going to hang that above the glass top about 6 inches above

If it were me, I wouldn't. That kind of heat even near glass would likely crack it eventually.

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Thanks!! Do you also have bubbler pools?