Changed Sand In Hayward Filter; Now It Won't Return Water To Pool

[McGinley]

This is my second year with a vintage Buster Crabbe inground pool. Last year was a successful one learning all the basics. At the beginning of this season I decided I should change the sand in my 270T filter. All went well and I've been filtering (with a few backflushes) for a couple of days. Today, however, I started vacuuming the bottom and at point the return flow diminished (I was using a skimmer basket and of course the pump basket, and not using the was setting--this is how I did it last year). I turned off the pump, cleaned all the baskets, backwashed and rinsed, and then restarted filtering. The return flow was strong for about 30 seconds and then went to just about zero. I backflushed and rinsed a couple of more times with the same results. Trying to determine where the problem is, I checked flow on backwash and waste settings, with positive results--the water flows properly. Then I ran the rinse for a minute or so and monitored flow, and just as with the filter setting, the flow (this time away from the pool) diminished. So, I know that the problem is within the filter and not within the return line to the pool.

Any thoughts? Could I have put too much sand in the filter? I was a little more than the recommended six inches from the top (more like eight). I used standard filter sand. Could it be a problem with the laterals? Could they somehow have been crushed? Why would it work for four days before this problem. And why after vacuuming? Have I put really bad slugde into the filter that won't come out?

Also, the pump is working well, pulling/pushing as it should (when the settings are backwash and waste.

[waterbear]

Have you checked the spider gasket in the multiport valve?

[McGinley]

Thanks for the response. Actually, I think the problem isn't how I described it. What happens is that when the filter and pump are taxed (usually when I vacuum the bottom of the pool, which is a bit cruddy after the winter), the water stops circulating. When I go to the pump, the basket area of the pump is completely full of water, but it's not getting moved by the pump (i.e. no flow). After this I need to start/stop the pump a couple of times, which seems to get the flow going again. My thought is that it's the impeller. Maybe it needs a couple of jolts to get going, and when there's significant drag, it stops pumping. I don't know. I'll probably start a new thread.

I appreciate your time, though.