I am (was)right smack in the middle of a SLAM attempting to clear a pool that was left unattended, and uncovered for over 3 years. (IT WAS REALLY GROSS, but significant progress was being made).
Something was causing me to lose some water daily, forcing me to top of the pool with water. I had checked all the hoses, around the pool perimeter, etc. and initially couldn't find where the water was leaking from. Then night before last I lost 4-6" overnight. (I thought enough is enough already something must be done to find the problem, and get it stopped).
I had read an article, (not sure where), that said with the pump off, with the handle in the filter position, to watch and see if the water in the site glass is moving at all, and if so the issue was water being lost out the waste line. Sure enough a little movement was in fact detected, and a leak from the waste line was found.
Apparently, my old multiport valve wasn't opening, closing properly, or properly sealing into the desired settings that were being selected, so I decide to just replace the entire part instead of trying to pinpoint which piece, or pieces were causing the issue, plus, the PS also confirmed that all the pieces on it were pretty well useless, and would need replacing anyway.
I decided since that section of the pump was already visible, and I was in a PS who had the supplies, this would be as good of time as any to kill 2 birds with one stone and go ahead, and replace the sand at this time too. Yesterday, replacing the MPV and sand, although very time consuming, appeared to go off without a hitch, or so I thought.
Plus, because I'd lost so much water, once the new sand was put in, and everything was put back together, it was again time to begin replacing the water I'd lost. (which was a lot). Since I'd put in new sand my pump 1st had to be backwashed for at least 2 mins, and rinsed for 30 secs to a min, before I could turn it to the Filter cycle, and filter the pool. But, my water level wasn't high enough to lose that amount of water out of my pool yet, so I waited, and monitored lines, seals, etc., to ensure nothing was leaking as the water level slowly rose.
Everything looked fine, no leaks anywhere that I could see.
The water level got high enough to do the required backwash, and rinse, to seed the new sand in properly, but now I can't get my pump to prime but about 1/2 way, or stay primed to properly get it done. I did do what I could on backwash, and then rinsed a little because I had to try other things to attempt to get the full prime back.
ALSO my site glass is only about 1/2 full of water when the filter is running too.
Here's the things I've tried to reestablish prime without success
1) I ran the pump on recirculate for a bit, it would try to pick up prime, but would then lose it, and blow water and air out the return port.
2) I opened the drain port at the bottom of the filter which caused the area where the filter basket is at to fill completely up with water, but as soon as it was closed the water level in there dropped to about the halfway mark again.
The things I've not done that may or may not be causing the prime problem:
1)I have not dumped water into the actual filter section itself, but it has filled up only to lose prime and drop that water level back to about 1/2, so I don't think a manual prime will help but if anyone who knows a lot more about this stuff than I do thinks it will help, I'll certainly give it a try.
2)I have not checked yet to see if maybe the impeller is clogged up preventing the water to properly pass through the system maintaining prime, or not, but perhaps that could be a possibility? When the basket was checked yesterday it had very little in it, and Was working fine before the MPV/Sand replacement but perhaps something was in my line from vacuuming that went into the impeller?? (If I check this can I just take off the 1 line where the filter basket is at , and not lose water, or does the return line also have to be removed to keep from getting flooded out?
3)The only other thing I can thing of that it would be is the O ring, that was put on yesterday is not sealing properly.
I really know very little about any of this so am I even on the right track with tracking down the non-priming issue? Is there something else it could be that I didn't mention? I really need to get that filter back up and running soon because I really don't want to have to restart my SLAM all over again. Thank you for your help, and have a wonderful day!!