10 gallons per hour? That is far far too small for your tank, I wouldnt even consider putting one fish in there at all. That means it takes the filter 4 hours to filter your tank once, where as you should be looking to have a filter that can handle your tank capacity at bare minimum 4 times an hour. Ideally you want about 5 or 6x an hour, have a look at the fluval U3 or U4 they would be good for your tank.
Wills