Quote Originally Posted by Wrisk View Post
So..... The pool volume is 25,000 ish? Cool. Just for info, since I put in a new cartridge the pool is crystal clear. No issues. I just have "helpful" people telling me to get a bigger filter. It sounds like I can put that off for a bit. If I get a c1200, is the 1.5 hp pump ok? Or should I still down size?
As you can see, in the post responding to Carl, the optimal flow rate for a C1200 is 45 GPM or less, far less than the 90 GPM Carl referenced. I'd recommend downsizing the pump, and saving the electrical costs.

Be VERY CAREFUL to clean your new cartridge promptly, when the pressure begins to rise -- don't wait till it's gone up 6 or 7 pounds. The C900 cartridge is more resistant to pleat collapse than the StaRite System3 cartridge shown above, but one it occurs, it's often irreversible. Unlike sand filters, there is no benefit with cartridge filters to allowing the pressure to rise. With sand filters, the dirt becomes part of the filter media during the last half of the filter run. This is not really true, and not at all needed with cartridge filters.

Instructions on how to clean your cartridge, without damaging it, can be found here; http://pool9.net/cart-clean/