I have a hob overflow its says 600gph but i dought it is.I have a mag 7 and i have to throttle it back about 1/2 way.I have 3/4 pvc return .It splits off so i have 2 returns one at each end.And the overflow has 1" pvc.Should i go with another overflow rated at 1200gph?I have a 55gal with a 33gal sump.If i need to buy a new pump i can. The sump does not seem to be getting enough flow through it.so i had to put 2 ph one in the fuge and one in the return side.Thanks in Advance