high tank temp issues.

the last week has been brutally hot in spokane. i have a really old house with poor ventilation and my tanks are too warm. most of my tanks are reading 86 degrees. did some cool water changes to bring the temp down. my question is is there a problem with doing this every other day to keep the temp down? i did 25% water changes last night. i don't want to KO my good bacteria and send my tanks into a cycle. my ac unit isn't big enough to keep the whole house cool, so i've been keeping fans in all the windows at night to try to keep the temp down but it's been in the mid 70s overnight, so even that isn't helping much. floating ice packs works ok in small tanks but isn't practical in bigger ones, and i'd need a commercial hotel ice machine to cool all of my tanks. i'd go broke buying bags of ice. any thoughts?

Take empty water bottles/pop bottles/etc and fill them with water and freeze them. Once frozen solid float them in your tank. 2L bottles would help with your bigger tanks. If you have enough you can have a set freezing while another set is floating.

I would also get an airstone going if you don't already have one to keep the oxygen in the water up. Warmer water holds less oxygen so you'll need one to make sure you don't lose fish or BBs

frozen 2 liter bottles are the way to go!

I do the 2 liter bottles also,....with the new AC unit it is not a problem now.

Even leaving lights on can heat the tank up. So for the time being turn off the tank lights. Keeping the glass top open with a fan blowing on the water can help. You can put a fine screen door mesh over the opening to keep the occupants from jumping.

Unless you run cold cathode lighting like I do

using ice in the tank can make a drop to fast in the tank temp,

take a large window fan or two how ever many you need to cover your tank take off lids ext and place the fan facing down on your tank.

i can keep my tanks in the low 70s doing this all summer in my room that is in the high 80s

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also try keeping the house closed up during the day 10am-6pm. no open windows and shades drawn. itll help keep the heat down, also keep the vast amount of powered devices off if you can. leave the windows and everything open at night with fans placed directly in the windows for intake of fresh air. this system seems to keep my place nice and cool up until the heat of the day has passed. GL to ya i know how lame desert climate can be mid summer

They also make cooling fans if you have money to burn.
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wow. thanks for all the quick responses. when doing my last water change i didn't fill the tanks quite as full as i usually do so that my AC 110's would have more of a waterfall effect and drive more oxygen into the water since i know high temps mean less oxygen. a strange side effect was that this also dropped my tank temps down 2 degrees even though the outside temp hasn't dropped one bit. it's actually a couple degrees higher outside. the filters are a little noisy but it's totally worth it for the sake of my fish. i always keep the house closed up during the heat of the day, and the windows open with fans in them at night. the cooling fans are a no go. i have too many tanks. i'd be broke in no time. i think i'll turn all the lights off in the tanks that i use lights also. thanks again.