Quote Originally Posted by PoolDoc View Post
On the commercial pools I've worked with? The grid membranes clog and have to be cleaned manually.

On a home pool? I'm not sure -- that's why I expressed some reservations, both about using a DE filter AND about my understanding of them in residential applications.

IF your filter is recoating properly, on start-up, there wouldn't be any problem. If there were problems, you'd be likely to see them as areas on the grids that were NOT coated with DE, when you open the filter for manual cleaning. Filter design matters in this regard. I know that some DE filters are designed so that the DE -- which tends to fall to the bottom of the filter when the pump is off -- is stirred up when the flow is restored. I suspect that some filters have mastered this design, but the System3 seems not to be one of those.

Sizing matters in an on/off situation, too. If the filter is oversized, then the normal flow may not be enough to 'unpack' the settled DE from the bottom of the filter.

I just compared the System3 and ProGrid designs, and the ProGrid *appears to be* setup more carefully than the System3, with respect to recoating. The System3 has an oversized exit port on the influent line, reducing flow velocity at the point where high velocity is needed to 'churn up' the settled DE. The ProGrid has either a standard, or restricted, size influent point, increasing velocity.

http://www.haywardnet.com/pdfs/repla...129Hay2009.pdf
http://www.pentairpool.com/pdfs/S284COM.pdf
Thanks Ben.

I've never opened up the filter for manual cleaning without back washing first (btw, I take it apart and manually clean it at the end of each season), so I can't say for sure if the grids recoat properly when the pump starts up. However, I've never had any problems with the water looking like it wasn't being filtered well nor any issues with the filter itself, so I'm assuming it's functioning properly without running the pump 24/7.

Overall I've been very happy with our DE filter.