I would prefer a power filter. There is a aquatech filter on it now rated for a 20g, but I dont want to rely on that little filter.The only other kind of power filter ive ever owned is the emp 400s, and they seem very good, seems like a lil much for a 20 though. There is going to be a pair of convicts in the tank about 2 1/2 - 3 inches long. What do you all think would be a good filter for this lil setup? I need a heater as well, but ive decided on a jager 100w with the help of a previous thread, itll be here in a couple of days. Thanks for any suggestions.