Use of DE in a sand filter

[Dee Smith]

Thanks for the information.

I have a Hayward S210T93 Pro Series High-Rate system that is 3.5 seasons old. The pump is 1.5 hp. I can install a valve on the discharge line and use it to restrict the flow.

I'll test with some DE first though.

Dee

[waterbear]

to use the DE in a sand filter you want to start with a cup of DE. First check your filter pressure. Mix it into a slurry in a bucket of pool water and pour it slowly into the skimmer with pump on. Check filter pressure. If it has gone up more than 1 psi backwash and start over will 1/2 cup of DE. If not wait 20 minutes and check pressure again. If it had gone up 1 psi then you are done. If not add another half cup of DE in a slurry of pool water, check pressure, and check again in 20 minutes. Repeat until your pressure rises by no more than 1 psi.
On future backwashes just add this amount of DE all at once in a slurry after you backwash. Backwash filter when the pressure has gone up another 7-8 psi.