I have a Hayward DE-3620 filter. I am just now opening our pool. I cleaned the filter grid in a muriatic solution for 24 hours. The grids looked brand new! I reassembled the filter, connected it to the plumbing, turned it on and got a psi reading of 15.5. In accordance with my owners manual, I then applied 4.5 pounds of DE through the nearest skimmer.
The 15.5 did not go up at all! I then ran the filter for a few hours in a very dirty pool. The pressure went to 26 psi. So, I backwashed/rinsed it and it dropped back to 15.5.
I'm sure the gauge is working because when the filter basket filled up with debris, the pressure on the gauge went down to 0.0.
Shouldn't the reading go up when I add 4.5# of DE? And isn't 15.5 unusually large for the initial pressure reading of a clean filter with no DE in it? I don't know whether I have enough or too much DE in the filter!
Help!
