I have a Pentair FNS filter with a Hi-flow backwash valve. The top was cracked at the bolt holes and leaking so I replaced the top along with the diverter gasket. I have adhesived the gasket in place as recommended and checked and re-checked the correct alignment of the valve top, but still when I turn the system on in the filter position, it leaks water out to the waste discharge outlet. I am stumped as to why this is happening. Can anyone provide help to fix this issue? Thanks