How to Clean Filter Grids and Dispose of Waste

Michael1 · Mar 17, 2019

I noticed that the filter pressure has gone up over time, even after replacing the DE. I have read that it is good to clean the DE filter grids occasionally. I'm new to this. One suggestion was to dunk the grids in a diluted acid bath in a plastic garbage can. After I'm done, what would I do with 40 gallons of acid water? It's not like I can just pour it down the drain. In fact, where I live, you can't just pour waste down the drain or in the street.

If anyone has suggestions for the easiest way to clean the grids, and how to handle disposal of the acid or other cleaning solution, let me know.

mknauss · Mar 17, 2019

Only reason to use acid is if you have calcification of the grids. Do you manage your pool water chemistry to TFPC levels and monitor your CSI? Do you have calcium scale build up in your pool? If not, then it is not likely your grids have scale on them.

Were does your back washing water go to? That would be the same place your wash water would go, I suspect.

ajw22 · Mar 17, 2019

Just use a water blast from a hose to knock caked on DE off the grids. Should be no reason for an acid bath. No cleaning solution required. Just clean water blasted on the grids. Give it a try.

chiefwej · Mar 17, 2019

If you have a lot of suntan/sun screen residue, a good soak in auto dishwasher detergent or TSP might be in order.

Michael1 · Mar 23, 2019

Thanks you everyone.

Mknauss, I do have some calcium scale near the waterfall from the spa to the pool. Otherwise, it is pretty good. I do keep the chemistry in line with the Pool Calculator on this site, although sometimes I don't check the pH enough, and it goes over 7.8 (usually not over 8.0). I generally don't backwash. I found that taking the filter apart did a better job, and the filter pressure stayed lower longer.

Ajw22, I do use a hose blast to clean the grids. It's the way to go.

Chiefwej, It's generally only me using the pool, and I swim later in the day when no sunscreen needed. Thanks for the tip.

I usually do use a hose to blast off the DE. It works well. I've just noticed over time, that the filter pressure just after cleaning with no DE has gone from 10 psi to 10.5 psi to 11 psi over several years. I thought I read that it was due to minerals collecting on the grids, and they needed to be cleaned with an acid bath.

ajw22 · Mar 23, 2019

pH between 7.8 and 8.0 is fine for the pool. Waiting to lower the pH when at 8.0 to 7.6 works out well.

Michael1 · Mar 24, 2019

Thanks, ajw22. I usually put acid in at 7.8, and drop to 7.5. Good to hear it is not a problem if it gets a bit above that.

I just cleaned the filters yesterday (full filter disassembly), and the pressure with grids with no DE is now 11.4. After adding DE, the pressure went up by maybe a a tenth of a psi. I thought it might be the gauge reading high, but I know when it gets to 13 psi, the water stops flowing to the spa, since it can't overcome the check valve. That hasn't changed.