As summer comes on, we will likely see many wanting some form of cooling for their tanks. This is often a place where we don't want to spend a great deal of money as it is a short term item. So that is a great time for a simple DIY fan setup.
This is one I built to replace a large fan as I wanted it set permanent but not stick out in the way. I found I could fit the small cooling l fans like used on computers into the space at the rear of the glass tops on this tank. This is a two inch space where the "normal" plastic shield that we cut to add filters and such is fit to the back of the glass panel.
Being a two inch space, I found a fan that is 50MM X 50MM X 10MM fits in just right. I find these on the auction for less than a dollar each from China if you want to wit a bit but I was in a rush so went with the $4 from the US.
these fans need a very small (.1 amp) 12VDC power so I can run four off one salvage power supply.
In my case, I already use the Inkbird temperature controller with both heating and cooling functions so I simply plugged the power supply into the controller.
Since my plastic was pretty well gone from being used with various equipment, I had to add a small strip of hobby styrene to hold the fans. I also added a plastic "tie-wrap" as a strain relieif on the wiring as I have to assume it will get snagged and pulled at different times. Better to prepare than to try to fix it after it is broken?
Wiring can be very simple with these as they only use two wires. Two wires from the supply to two wires from the fans but in this case, the polarity does matter. Since we are working with such low power and nothing delicate, it is simple to hold the wires together and see if the fan runs. If not swap the two wires. Totally safe to do and much easier than trying to tell you which color will be best as the colors vary from one to another.
I found I got more air moved when I installed two blowing into the tank with the other two blowing out. You can't blow or pull air when there is not way out.
Maybe you can use the idea for a simple, cheap and easy way to cool the tank?
Summer's coming and it get hotter every year, so we have to be ready to adapt.