I'm new to this board. This is our 5th summer in our house. We've had problems with something pool related every year. For the last 2 summers DE shooting back into the pool upon start up has been the issue. We have replaced every single grid, the valve, etc. Manifold is the only thing that has not been replaced, and we're not even going there at this point. We have a 20K gallon inground pool with a vinyl liner. Our system is pretty old and has a .5HP pump on it. Right now we have a 36 filter and are deciding between a Hayward Pro-Grid and an Pentair FNS. We will also get a multiport valve even though our push pull is brand new. I have 2 questions. For those of you with a lot of experience which would you pick? Also, my husband does construction for a living, but is not a pool man (although he has taken apart our filter to replace all the parts 100 times). Is filter install pretty simple? (he definitely can do the pvc himself). Thanks in advance for any advice. We're hoping that replacing our filter will solve the problem of DE floating into the pool upon start up.