I have a new Summerwaves Sand Filter that has only been running for about a week now. The water flow is pretty slow and the psi reading stays at 0 all the time. I tried backwashing and rinsing several times without any improvement, so I was hoping someone here may have some suggestions on how to fix it. Here's a link to the filter that I have: Summer Waves 10'' Sand Filtration System | Polygroupstore