Why Does DE Material Stays At The Top Of Filter And Grids?
by John Blausey
DE filter was full of algae as was pool. Back wash did nothing as water always ran clear. Removed grids and cleaned. Grids look fine. No rips and cleaned up well. Re-installed and re-charged with DE. Had a leak so I removed the filter lid to clean and install gasket. I noticed all the DE was on top of the assembly and only coated the top 1/3 or so of the grids. The pressure while running was 8 to maybe 10 PSI. It's never been higher even before cleaning. I suspect my valve needs to be rebuilt. It's a 2 position slide valve. Also I am wondering if there is a clog or broken impeller that is causing the low pressure. Would low pressure cause the un-even coating on the grids? Thanks for the question John I get more questions about DE filters than any other pool filter. They're the best in keeping your pool clean, but they are the most troublesome. A problem could come from not having the proper flow of water through the system. A clogged impeller could be the reason. Turn off the system, remove the pump basket, and check the impeller. If it doesn't turn freely, you may have a problem. Most of the time residential pools run anywhere between 20 - 60psi, depending on the horse power of the motor. Most of the time a 1/2 HP pool motor is fine. Be sure you're using a real DE scoop, not a coffee can. You'll get the most accurate measurement with a DE scoop. Scoop out the DE with the coffee can and pour that into the DE scoop until its level. Just like measuring flour. Always premix the DE with water in a large bucket, maybe a 5 gallon bucket, to get a nice slurry, then pour that into the skimmer. It otherwise might clump up in the filter rather than properly coat the filter grids. Sometimes the problem with not doing a premix is that the DE might not spread evenly inside the filter. You'll get big clumps and bare spots on the grids, usually near the middle or corners, and a thin cover in other areas. You can also check the nibs (if equipped) on the manifold, top and bottom, to make sure they are not broken or cracking. The nibs are on the manifold that hold the grids in place. DE Pool Filters DE Pool Filter Maintenance Hope this helps and let me know how this turn out for you. Others have the same problems. Have a great swimming season and please remember to sign up for my free monthly E-Zine newsletter. Robert |
