High temp problems


New member
Okay, so my tank has temperatures that range from about 79 at night to 86 in the day. I have a 55 gal, with a 30ish gallon sump. It just finished cycling, and i added a peppermint shrimp to take care of the aptasia that was starting to return. He was in there for a few days, only came out at night, and then, yesterday, the water got up to almost 90, and the peppermint died. I am to scared to do anything with my tank until i get the temp down. Don't want to waste another 10 bucks on another shrimp either!

The only lights i use right now are 4 55 watt pc, and they get sort of hot, but it was never a problem when my tank was fw with the same lights. What could make the water so hot? At first i thought it was because of room temperature, but the water is hotter than room temp, and even the air conditioner didn't lower the temp. I also tried water changes, but that didn't work either.

Maybe the heat is from bacteria? sounds unlikely.

What causes this and how do i stop it?


New member
What is the temp of the room?
Do you have fans?
What pumps are in the water?
Lighting cycle?

If have found that PC light seem to get really hot (especially when the bulbs are older) 90 is WAY too HOT!!. I have a tank in my garage and it reached 86 in this Florida heat, I added a fan blowing across the top of the tank and now it stays around 82-84.

Your high temp is one problem and the other is the temp swings. You would hope to keep the temp range around 2 degrees(low to high)


Premium Member
If you're having high temperature problems with PC lights, as opposed to MHs which are usually a bigger culprit, then it may really be a difficult thing for you get under control without a chiller. First, though, try the fans...Have one blowing across the top of the tank so that the heated air under the lights would be dissipated and also have a fan blowing across the sump to foster evaporation, which has a cooling effect. This really should lower the temperature in your system, but saying exactly how much is difficult to do. Remember, with more evaporation, being attentive to topping off the sump becomes more of an issue.

Once you've tried those measures, if the temp doesn't stay steady at a more acceptable temperature....go and get a chiller. Once you do, peace of mind comes with it.


New member
You have 220watts of PC lighting on that tank. This is the source of the heat. Try the fan across the lights. If nothing works then a chiller is inorder


New member
okay so i put some wood blocks on the lights so they rest at about 6 in above water now. They used to be about 1 inch above water. I also put 2 computer case fans on the sump. I would put them up on the top, but i don't think the power cord is long enough. I will try.

Last night i opened my window and opened the stand doors where the sump is. Overnight the temp went from 85 to 75! I think the lights were the cause of all of the heat problems because once i raised them up, the temp remained constant (as apposed to rising).

Funny story. Before i opened my windows to my room, i came home from poker last night at about 11 and opened my door to turn the tank lights off. I keep the door closed because my family complains of the smell. :lol: Anyway, i walked in and almost choked. It felt as if i had just walked into Hawaii. My room was so humid i could barely breathe and the temp was way up. The tank temp was constant though. In just 4-5 hrs the fish tank had raised the temp of my room significantly!

I will give my tank a few more days with this setup to see how the temp does. I think it is okay, but better be safe. Thanks for the help.


New member
i found the peppermint in the tank, alive and well :lol: I guess i must have pulled out his molted shell and thought it was his corpse

water temp is still at a constant 75 now!