Hi Careen,
I was plagued with high tank temps (86) last summer and since then I've managed to drop the temp 5 degrees this summer even though I've got several more pumps and powerheads in the tank. Here are some suggestions.
1)Keep the room AC turned to the lowest temperature you can afford. I've found that 76 degrees doesn't run my power bill up too high, but by all means don't turn the AC off when you leave for the day. I'm in the AC business and I often go into houses where the AC isn't working and find temps in the mid 90's.
2)If your tank has a lid or top on it leave it open or remove it. If you have fish that may jump you can get some eggcrate at the hardware store and cut it to cover the opening.
3)Fans. The more the better. Point at least one at the top of the tank. If you can get one to blow across the surface you will increase the tank's evaporation thus cooling the water. Also have more fans to blow the heat from the lights away. I use several fans in the room to keep the air circulated and even then when I walk near the tank I can feel that the air is warmer. I'm getting ready to add two more tower fans in the corners of the room where the tank sits. These fans aren't too bad looking and are approved by the "executive committee"
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4)Use ice for topoff. I only do this in extreme conditions and I would be reluctant to advise this on a 10 gal tank without a sump. I only do this in the sump and with a 120 gal tank it's real slow bringing the temp down. But last year when my tank got to 86 I was feeling desparate. If you decide to do this then do it slowly. You don't want to drop the temp too fast.
5)Change your lighting cycle. Run your lights at night when it's cooler. Leave them off during the hottest time of the day.
BTW. What is your tank's temp?
HTH, Rick
