How to control tank temperature in summer

[kathreen]

I live in the midwest and don't have central a/c. I have a wall unit but typically only run it when it becomes miserable (mid high 80s and humid), otherwise the expense is enormous. Currently the highest I have seen the tank temperature get is 81 when my apartment thermometer also said 81. I have a 3 gallon tank with two adfs (one male, one female.) No filter, heater is out, and I haven't been using the light. The tank is located on a table in the middle of two rooms on a wall. I typically have a window open to regulate the temperature somewhat in my apartment and they are in that path though 10-15 feet away. I have two questions:
1) What is the highest temperature the tank can get before I should be worried?
2) Any ideas how to cheaply cool the tank? This has to be something that is safe and used when I'm at work or on vacation.

[mpmistr]

African Dwarf Frog (Hymenochirus) which is a tropical species, should tolerate 81F. However this is probably still a bit on the warm side, but I believe on the upside of tolerable for this species. Lowering the water temperature slightly may be more ideal (77F).

1. Get a bigger tank!! Why? Larger volumes of water are more stable and less prone temperature (and overall chemistry) changes. A 3 gallon tank is simply going to shift to ambient room temperature VERY quickly vs 30 gallons of water. Even a 10 gallon tank (Walmart $12 dollars) will hold temperatures a lot better than 3 gallons.
2. Place a box fan (or similar fan) next to the tank, circulating air over the tank may drop the temperature a few degrees.
3. Use a screen lid rather than a glass lid, more evaporation means cooler temperatures, but you'll need to replace the evaporated water.
4. Do daily water changes with cooler water (this would work better with a larger aquarium).
5. If temperatures really get out of control, use a ziplock bag of ice to bring the temperatures down (I had to do this last year with my african clawed frogs when my central A/C unit broke down and outside temps were 100F+ all summer).

That's all I can think of for cheap methods.

[rodsboys]

Way back when I kept newts I use to keep several per tank if those "ice packs", the ones that are plastic and you just keep refereeing them.
81 is ok for ADF's for a little while so you should be fine.
At the end of the day it is hard to keep a good balance on a 3 gallon though, it swings too far in either direction to quickly.

[mpmistr]

Also placing the tank on the floor may help, it will be a bit cooler down there.

[kathreen]

Thanks everyone for your helpful comments. I plan on buying a 10 gallon tank today, after that I'll probably start using a fan and then possibly putting them on the floor as well. I'll keep you posted to say how it is going.

[kathreen]

So I bought a ten gallon tank, but I'm not sure it is helping. This morning I put in some cooler water and ran the heat all day. This morning the temperature said 79, this evening it says 81. My apartment temperature also followed these numbers (exactly.) It got out to 84 today. I have one of those thermometers that you stick on the outside of the glass. I'm wondering if this isn't an accurate measurement method. I looked at Walmart at the ones you stick in and float, but those had a bunch of stuff in them that made me nervous for my frogs. Any suggestions on other thermometers?