Ok, new to the pool world but I have a good grasp on most stuff mechanical.
Yesterday we had a huge pool party in several waves - adults in the morning and teens in the afternoon. All went great, I ran the filter full time all day as expectedly the swimmer load was crazy high. As the day progressed I noticed the back pressure building as I expected it would - I normally run 7PSI with a the filter clean, and it crept up - 10 psi around afternoon, 12 by dinner, and close to 16 or so by sunset. I figured I'd be in for a backwash today after letting the filter run a good portion of the night to polish the water up again (as it did, things look nice and clear again this morning), but what surprised me was that I checked back pressure today and Its dropped back to about 9psi as of this morning.
I thought once it came up it would stay up, no? Did the filter cycling on and off after its nightly run cycle (I have it on a timer) allow debris to "resettle" in the sand and flow improved, or something?
Is this normal?