DE in a sand filter???

[The Raddish]

Here's a question. My new Pentair Dynamo 3/4 Hp two speed pump is being delivered today. I plan on running the pump on the low speed setting for about 12 hours a day (turning off at night), and only using the high speed setting for vacuuming, running the fountain when we have guests, and during high bather load.

So, if/when I add DE to the filter, do I add to 1lb increase on the low setting, or the high setting? I'm assuming that I add to a 1lb increase on the low setting, but wouldn't that equate to more than 1lb when it is on high?

[CarlD]

Absolutely add the DE when running on high. Do not do it on low. The pressure may well be too high if you add it on low.

I have a two speed and use the DE and always add it when the filter's on high--it's easy because I backwash on high and I add the DE right after I backwash.

[The Raddish]

Thanks Carl. That's the answer I was expecting.