This is what I originally said happened to me I too did not find any issues with the housing so I tried impeller and shaft it did not work for me so I replaced the entire assembly. Maybe you will get lucky try the impeller and shaft. It just winds up costing you more if it doesnt work thats why I posted my experience trying to help you out I had the same argument you did 100 dollar part 250 dollar filter but in the end its a good filter so the repair is expensive but a solid one. Here are your options try a new impeller with shaft probably wont work, remove sand or raise the intake if you keep the sand it will probably happen again later, buy a new filter, or just spend the 100 bucks replace the whole impeller assembly. You have gotten solid advice here from other members with the same issue. So post up when its done so we can learn from your experience.
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