We have an Aquamedic Anthias 120 which is 550L (122g) without any powerheads. The main pump is 3500 lph (925gph). I know that it needs a powerhead but not sure how many it needs.
Well if my maths serves me right I have about 6.36x per hour. It was more I wanted to get some flow to parts of the tank where there isn't much. The main filter outlet comes into the water at about a 45 degree angle in the middle of the tank - which means only the bottom left corner is getting enough circulation. I don't want the whole tank to be flowing, I would like some parts where the fish could rest, it is just that the right side of the tank isn't getting much circualtion.
How big is moderatley big... sorry I haven't had much experience using powerheads, and would it be better to get one moderately sized one than two smaller ones?