DIY cooling solutions?? with fans

That's exactly how fans cool off the water. It's evaporation cooling. That is how I'm cooling my little 20G tank right now. I have a dual 12V computer fan running. Even with my 70W HQI on my tank, my temp sits at 78º at the heat of the day. I will get about 1G of evaporation a day though. My minichiller should be coming in soon.
To Wally, if you can save up about $200, you can find a good mini chiller for a small tank.

 

so you think a chiller would be better?

 

I think chillers are more stable and more reliable than fans. A fan can stop working if too much dust gets into the ball bearings, if the lubricant dries out, or if it just stops working. At least with a chiller, it's controlled so it won't over cool (mine will get down to 72º if I forget to remove it at night) and it won't evaporate the water which will alter the SG of the tank.. My first clip on fan broke loose and fell into the water, talk about a scare!

 

For my Tanks. I have an inline heater connected to a chiller. I set the heater to ~ 80 to 84 degrees and I set the chiller to 70 degrees, they are connected inline to each other and I have a small pump that circulates water from the tank ( can be a sump) through the heater, then through a UV light, then to the chiller and back to the tank. I don't actually use the thermostats on the heater or chiller. I have then both connected to a "master controller". I set the controller to 78.6 degrees. if it drops down, it power up the heater ( I set the heater to 82-ish just incase something goes wrong), when the tank warms up, the controller kick off the heat. if it gets too warm, the chiller kicks in. The controller has an alarm if the temp goes outside the normal ranges.

It cost a bit more adding a heat/cool controller plus the inline heat and chilling unit. HOWEVER, The most important part to me. It's like Ron Popille (sp?) I set it and forget it. My set up has been running like this for 2 years. Heat/cooling is not something I worry about. I paid a bit to set it up, but I don't need to turn on fans, or off. I don't add water that often to my tank. I spend more time looking at my first then working on the tank.

 

my ideas are all roughly the same i used 2 old pc fans
i cut two holes in my lid either side of the mh light attached the fans and linked them to a 12v battery which charges on a solar panel. without the fans the temp rises upto 10f but with both fans runing it actualy drops by 1f which is no big problem an it goes no further i find that as long as you have some kind of serface above the water the water vapour condences on the lid and runs back in the tank so i get very little lose