I have a feeling I know what the problem is. The pool was a big algae pit before opening. I went to the pool store to have them show me the set up if I removed the Mineral System. I have 2 eyelet returns on the pool, upper and lower. I asked if I had to open the bottom return, since I cannot get to it without getting in the "swamp". He told me I did not need to worry about it until I got the pool clear. I have a "T" shaped attachment, so that I can attach both returns, but had to close off the one going to the lower return, until I can open it.

From doing some reading, I can see this can cause high pressure. Although my pool still has some green in it, I guess I need to get in and open that return. If I backwash, the gauge goes to normal readings, but once filter is back on, the pressure goes right back up. We'll see if I can rectify that situation if it changes anything.