Expert: roger - 6/30/2009

Question
i have a hayward pro grid de filter system 48 sq ft. pool water turned green with alge filter system doent seem to be filtering right.pressure way to high. cleaned backflushed several times with same results. replaced grids with brand new ones with in few minutes same think pressure rises and water dosent filter like it should. back flushes fine. can the green alge be clogging the grids not allowing water to filter back to pool. they are green but not alot of solids on filters.

Answer
Take the DE apart again and clean the grids again but reassemble the filter without the grids and let them dry out. Get a strong algaecide and dump into pool run one day no grids. Day two shock the pool with two jugs of liquid chlorine. Day three install the grids back in the filter and run 15 minutes no powder then charge the filter with DE powder through the skimmer and record the pressure and bleed the air out as well. This is your operating pressure and dump in another jug of liquid and green should be gone in a day. Each time you backwash you must recharge with DE powder. Over the summer the pressure will gradually increase each recharge. When you close your pool make sure you add algaecide for the winter. Another good thing to do is take the grids out, clean and store them till spring.