Bring water temperature down

[csordner]

I have a 220 gallon tank and I am trying to bring my water temp down from 82 to 78 degrees. I have tried to leave all lights off and I have tried to keep the keep access doors open for ventilation. I have even used a fan to blow out hot air. I guess I am really wanted to know if anyone knows how to make a homemade chiller.

 

[sly]

I've seen people coil up plastic tubing in one of those dorm sized refrigerators and used a powerhead to pump the water in and out of the tank through the coils...
Do you have a glass cover on your tank?

 

[scsinet]

Homemade chillers are usually not practical. Any designs based on refrigerators or freezers will not work, for a laundry list of reasons I won't bore you with.
I am a die-hard DIYer, but chillers I do not attempt to make on my own. It's just not practical, and nothing homemade will be as efficient and/or reliable as a commercially made unit.
I'd look at passive solutions first, as sly was saying, the glass cover, evaporation encouragement, etc. In a pinch, keeping your home or at least the room the tank is in at a lower temperature will work well, but may, over time, exceed the cost of a chiller in what it costs in energy bills.
If none of those are feasible, buying a chiller is the route to go.

 

[csordner]

I do have a glass top. I have tried to leave the lid open.

 

[scsinet]

Try removing it entirely. It usually makes quite a difference, and we're only talking about a few degrees here.
You may also try directing a fan across the top once you remove the top.

 

[sly]

Agreed. As little as you are wanting to cool your tank, I bet removing the glass cover will solve your problem. I suggest putting an egg crate/light difuser panel on in its place and adding some fans to your canopy to draw the hot air out. I did this on mine and it changed my temp from 84 to 78. By having a glass cover on your tank, it's exactly like putting it in a green house.