Clean pressure after adding DE to sand filter

[Abigail K]

Reference to http://www.troublefreepool.com/threads/84056-Fighting-my-second-algea-bloom-in-2-years

Should clean pressure after adding DE to a sand filter be the pressure before adding DE, or after?

It's not explicitly stated but based on the context I believe it should be the pressure after adding DE, can someone confirm this?

Mods/admins please merge if appropriate.

 

[mas985]

It would be best to start with a clean filter and then when you add DE to the sand filter, you don't want the filter pressure to go up more than 1-2 PSI from the clean filter pressure.

 

[Abigail K]

More specifically, what is the appropriate "clean" pressure to base a backwash upon?

 

[mas985]

I am not sure I understand your question. There is no appropriate clean pressure. Every pool is different. However, everything is based upon the clean pressure so that is the baseline. Clean the filter when it rises 25% above clean pressure. If you are using DE, then the clean pressure becomes 1-2 PSI higher than without DE.

So for example, if your normal clean filter pressure is 10 PSI, adding DE will raise it to 11 PSI and then you can clean the filter at about 14 PSI.

 

[Abigail K]

If you are using DE, then the clean pressure becomes 1-2 PSI higher than without DE.

So for example, if your normal clean filter pressure is 10 PSI, adding DE will raise it to 11 PSI and then you can clean the filter at about 14 PSI.

That's what I wanted to know, thanks.