I'm looking for a small circulation pump for a 20G long. Adjustable would be great, if possible. Don't want it to be too powerful. Any suggestions? Also possibly a small cooling fan. I saw this one online: http://www.drsfostersmith.com/produ...=pla&catargetid=530005150000091181&cadevice=c My concern would be evaporation and noise, which was pointed out in a couple reviews. Any suggestions?