Humidity too high

[br00kex33]

Hey guys! I’ve recently adopted two hermit crabs. One is medium sized and the other is small but in a shell that’s way too big. They are housed in a 40 gallon topfin aquarium with a glass lid. There’s about 3 inches of dry play sand in the tank currently. I have bought eco earth and more sand to mix to bring it to a sand castle consistency and get it to atleast 6 inches but I worry because my humidity is already at 92% won’t this bring it up more by adding water to the substrate. I currently have one UTH on the side of my tank that keeps the temperature around 72.5 degrees farenheit and another on the way to bring it up even more (hoping that will help with humidity. Just worried the humidity is too high as I know ideal range is about 70-80%. Do you guys have any recommendations? Should I wait until additional heater comes in and see if that drops the humidity before messing with the substrate? There are two shallow pools one salt one fresh. Plan to get bigger ones eventually.

[emayers]

Priority is to get that extra sub into your tank so your guys have molting and digging room. High humidity doesnt hurt them. High humidity can cause mold to grow on your wood and food. Extreme humidty can cause water to drip down the sides of your tank and flood your sub, but thats extreme.
To fix your problem, you have a few options. You can crack the lid to let some humidity escape. Adding a fan for circulation can drop humidity. My suggestion would be to possibly use a heat lamp. Heat lamps are usually discouraged since they tend to lower humidity, but your temp is on the lower side so adding one could take care of both of your problems. I did that with my tank and solved both my low temp and high humidity.
Good luck!

[curlysister]

As already stated, high humidity isn't going to harm your crabs at all. And the condensation running down the inside of the glass can only lead to flooding if it is from extra water being added to your tank - if the humidity is coming from the sub, then condensation is happening due to the temp difference between inside and outside the tank, the water that runs down the inside will just go back into the sub where it came from.
While 72.5 is a safe temp, it is at the lowest end, so bringing it up a bit isn't a bad idea. I would get the sub set up and moistened, add your UTH, then see what the humidity is. You can always vent the tank a bit if you need to, but the increased temp will lower the humidity even from a UTH.

[br00kex33]

Thanks guys! They don’t move every night I think they are a bit depressed. Is this normal? I’ve only had them for about a week. Should I get two more to see if that won’t help encourage them to be more active?

[curlysister]

Crabs will be more active if you get your temp up closer to 80 degrees. Have you mixed in the eco earth so that the substrate is moistened to sand castle consistency?

[br00kex33]

Crabs will be more active if you get your temp up closer to 80 degrees. Have you mixed in the eco earth so that the substrate is moistened to sand castle consistency?

Yes, substrate is a 5:1 ratio of play sand and eco earth and is 6 inches deep. Do you have suggestions on a good UTH heater? I’m running two on both ends of the tank and that’s keeping my temp around 75 or just slightly below. Not interested in heat lamps as they are dangerous and I know friends whose houses have caught fire because of them, thanks!

[curlysister]

What brand of UTH are you using now? If they are able to be insulated over top, try that to see if it will bring the temp up.
The UTH that do not have a sticky side and have to be attached with tape are better than the sticky ones - I am having a brain fart about brands, but the ones from Reptile Basics and the Ultratherm brand are good (there is another that I can't think of right now).