New to the site, but been reading for a while. Hopefully this is an easy one. Just set up brand new Summer Escapes 16x48 AGP with Intex CS15110 SWG and sand filter. Seems to be working OK except the pressure gauge on the sand tank reads ZERO and the water is mirky. I've vacuumed twice and it just looks like the water is running straight thru without being filtered. After a few hours, the particulates settle back to the bottom. I've backwashed twice, and check the water. Chems seem right where they should be, but I'm concerned the filter is not working. Any suggestions? Thanks in advance for your most excellent help.