Hi, not sure if this is the correct place to post but here is the problem....
We have a pool / Spa combo and I suck the water from the spa and return it to the pool to skim the water more efficiently. everything has been great for the past 15 years but recently when I turn off the pump and come back an hour or so later I find that the DE has drained from the filter back into the SPA. I havent tried using the pool skimmers and turning off the pump to see if its flowing back there because its a lot easier to vacuum it back from the spa .
any ideas what could be causing this?
from what I can tell there are no leaks anywhere in the system (i dont see wet areas)