i mean a fan on top of your tank. Normal house fan. i done that before. after which i place it on top of my sump. so that i can seal my table fan. and it works. On for 24 hours. Temperature maintain 28 degree. And my coral are happy.
Those are history. I've gave up these hobby 2 years ago. But after joining this site and saw every body tank, i think i'll start again...from scratch.