After having our pool reconstructed over the last 4 months, this morning we turned on the filter system for the 1st time. The PSI used to be up around 19-20. Now, it seems to be sitting at 10 PSI .. I let all the air out of the filter tank and it still doesn't seem to want to get higher. Otherwise, I have not opened up the filter at all since turning it off 4 months ago.
The only difference in the new build is that we added a dual filter/drain in the deep end - that of course runs into the skimmer basket. There is a plastic hinged "valve" (not sure what to call it) that swivels over the hole in the skimmer - to allow the drains to suck water, or closed thereby no water flow through them. I have not tried shutting them off to see if that makes a difference - should it?
What can cause a lower-than usual PSI in the Filter?
Thanks in advance.