New tank topper sucking heat

[Alexisr.17]

Hello!
As it says in the title, I recently put a 25 gallon exo terra tank topper on my 90 gallon. Before I put it on, the tank was steady at ~83° F, and 86% humidity, (was warning and making it humid for the topper incase this happened), but now with the tank topper on, the humidity dropped to 81%, and it's at most 77 F in the middle of the day, often even 75 at night. The actual tank topper is at 86F and 70% humidity, which I know isn't good, but I can't get it to balance.
I have "seed warming planting mats" that are along the entire back of the 90 and one side, and a single heating mat on the tank topper to try and push warmer air back down to the bottom tank, which raised it to 87F.
Should I put a fan? More heating pads? I only have 2 of the 4 up right now (other 2 are molting), and they haven't even tried climbing the multiple ways to the top...should I be worried?
Any tips?
Sorry, im new here and can't exactly figure out how to post photos!!!

[curlysister]

To post photos, you need to use the TapaTalk app, or post a link to a photo sharing website.

Heat rises, so I wouldn't expect the heat mat on the topper to push any heat downward. How long has your topper been on? Has it been enough time to all level out?

[Alexisr.17]

The tank topper has been on for about a week, so I thought it should have. How long does it take for it to even out? Also, this morning the tank topper had jumped to 92 f and 65% humidity...is that dangerous for the crabs? What can I do to help even it out?
Thank you!!

[JoeHermits]

The 90s aren’t dangerous so long as the crabs can get away from the heat when they need to. A fan would help but you’d have to protect it from the crabs so they don’t damage the fan or themselves


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