Swimming Pool Blog
by Rob Cox, September 24, 2012
Annual D.E. Filter Cleaning & Inspection
Autumn is here, and this weekend will note the first day of fall. Time for the annual chore of cleaning and inspecting your D.E. pool filter. If you are a snowbelter, and are winterizing your pool, cleaning and inspecting your diatomaceous earth filter grid assembly is part of any well-done pool closing.
For those that use their pools nearly year round, this important filter maintenance can often be forgotten. Some DE filter grids may need the cleaning more than annually, if undersized or in high demand situations. If your filter cycles (time b/t backwashes) have diminished, that's always a good sign to remove the filter grids for a manual cleaning.
Backwashing never gets everything out, maybe 60-80%. Over time, excess DE powder can build up, and bridge the filter grids, creating areas of poor filtration.
D.E. pool filter grids don't really do the filtering of your pool water - they are the sieve on the other side of your DE filter powder that strains the filtered water, collecting it and directing it to the manifold, where it exits the filter tank.
They are (Filter Grids) however, a very important part of the system, and have two main jobs: 1. Allow water to flow through, and 2. Dis-Allow DE powder from flowing through.
At least once per year, it's important to:
- Open up the filter tank carefully
- Remove the grid assembly
- Hose Clean thoroughly
- Inspect for damage or wear
- Reassemble filter tank carefully
If you are have noticed your starting pressure slowly rising over time, or if you are backwashing more often now than you used to, soaking the grids in a solution of Filter Clean will restore them to like-new performance. DE grid fabric can get clogged over time with oils and minerals, which hose spray won't remove.
To use Filter Clean, after hosing the grid assembly very clean, attach the spray top to the bottle and spray your grids with the combination grease cutter and mineral dissolver. The chemical works quickly. Rinse again thoroughly and then you can replace the grid assembly in the tank for winter storage. I prefer this type of spray on DE filter cleaner to the type of chemical that requires a soak the grids in overnight.
To Inspect your DE filter grid assembly, look for:
- Tears or rips in the fabric, especially at the seams and the bottom center.
- Broken tabs on the top, where the grid inserts into the manifold.
- Cracks in the manifold (don't let it fall over!)
- Missing or damaged air bleeder screen or sock on the manifold.
- Loose assembly; missing through wing nuts on thru-bolts.
- Missing or damaged standpipe o-ring; where the manifold fits on.
- Mis-spaced or mis-aligned grids.
An annual inspection and cleaning should keep your DE filter running in tip-top shape. But don't wait if your filter starts acting funny - you can do this anytime!
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