Water Temp Problems

[commander]

I am having the opposite problem most people seem to have. I can't keep my water temps down. Air temp yesterday here was 104 degrees. When I got home at about 6pm I checked my system and the water temp in the fish tank was approaching 90 degrees. The goldfish didn't seem to be too stressed but the plants looked a little wilted. Since it is just April and based on the temps we had last summer, I am looking for ideas on how to cool down the water in the system rather than warm it up. Anyone got any input?

[keith_r]

is your fishtank shaded 100%? any insulation?
shade the sides of your growbeds, and shade your gb's in the hottest part of the day
even having a fishtank buried, in heat like that, the growbeds are going to transfer lots of heat to the water.. constant flood may be a bit more "stable" but given a small volume of water, it will still heat up before the end of the day, and will hold the heat longer into the night...
what kind of humidity do you have? (maybe a mister over the gb's)

[David - WI]

It kind of depends how many days you think the average temperature will be over 70 and how many gallons you have to cool?

For a smaller system, I think I would look for an old chest freezer and freeze up a bunch of plastic milk jugs full of water. Depending on how hot & sunny it's forecast to be that day, I would drop 1, 2, 3 or 4 jugs in the fish tank or sump (you would have a little "trial & error" finding out how much it took). (http://www.advancecarmover.com)

The next day, put those jugs back in the freezer and put new frozen ones in the tank.

For a bigger system, I would probably fill the chest freezer with water & RV anti-freeze... then pump the fish tank water through there in a few coils of PEX. You could use a thermostat in the fish tank to start & stop a small circulating pump when the tank got too hot. The nice thing would be that the freezer could catch up at night and have a big reserve of "cold" ready for the next day.

I guess another option would be to use the chest freezer as your sump, and tweak the thermostat to get it to run at 65F - 70F. It would probably come on mid-morning and run into the early evening?