We got our first pool when we purchased our new house last year. When we opened it this year and replaced the failed liner, the company who did the maintenance gave us some advice how to maintain the pool. I never followed his advice as I learned about TFP and have been doing it since.
The gauge shows 10 psi when off, and fluctuates 10-16 psi while running, most I have seen it is 16 psi, but currently it is back down to 10-11 psi. It has been in use since the end of May. Is it normal it goes so long without having to be back washed? I keep the pool very clean, I have a Dolphin M400 and I skim the leaves every day or other day at best. The chemicals are in perfect, so I know it will last longer, but seems just worried I'm going too long.
It seems to work really well, the pressure changes, so I know it isn't "stuck" but usually is only 10-12, at some point it was around 16 but after getting the robot and keeping the pool clean I rarely see it over 12-14.
I am guessing they backwashed it when they did the liner and "opened" the pool. They mentioned they found the DE, and there was DE around the skimmer hole.
The filter is a Hayward DE7220.