If the weather is very hot over where you are, simply take the heater out and just moniter what temp it is yourself, or just put a bottle of water in the freezer and cool it down and then put the bottle in the tank to help lower the temp.
anything up to 28 (for a few hours, until it cools down at night) is really not going to stress them out tremendously. Wilder posted this link to a helpful article.
Edit: and to be honest, my one tank nearly hit 30 a couple of weeks ago ! luckily it was only for about 5 hours or so and the fish seemed absolutely fine and were swimming and eating as usual. I also just switched the lights off.
That's quite a good article above and the recommendations about increasing the general heat in the tank is a good one. Thereby the fluctuations are not that great.
26? could you translate that in US degres? ROTFLMAO. Keep in mind many of us are on the other side of the pond. 26? still cold in UK? It's like a nasty 90 something here. Thats 90 degree in US # LOL
Heater? sheesh I unpluged all mine a few months ago.
danny
deg c to deg f = devide by 5 multiply by 9 and add 32 and hey presto
eg 20 degc = 4x9=36 +32 = 68 deg f
You guys are lucky. We Brits have the heating on all the time