Sand Filter PSI question- new pump a little disappointing

[KurtV]

Your numbers look normal to me. I'm running a 1.5 HP uprated pump on a 300# sand filter and get about 17-18 psi when the filter is freshly backwashed. My pump is oversized for the filter (or the filter is undersized, probably the latter). Your pump may be a bit undersized but that's a much better situation than mine.

What's the flow rate of you setup? What's the turnover time for you pool? I'll bet both are just fine and if so, you should be getting great filtering with this setup. If you want to "polish" the water even more, take Carl's suggestion to add a bit of DE.