I went through each of these threads as I have a suction side leak. My problem is slightly different though. I get bubbles out of the outlets and twice now my pump has lost prime. However each time after I backwash it primes fine again. I just changed the sand in the filter a couple of weeks ago. Is it possible that the new sand is working so well that it loses prime?

I usually backwash every 2 days or more if I'm vacuuming.