So am looking at getting a cross flow pump for my 40B. I'm just not sure if the CP-25 will be enough since I have the Fuji Pink sand or if I should go with the CP-40. Reason I ask is I have the RW8's and it's too much flow and I like using the else mode. So once the cross flow pump is in place I can sell the RW8's and get the rw4's.