Sand in Pool

[gilera]

I have a constant problem every time i turn on pump i get an initial shot of sand in pool. I have had this problem for 6years. I have stripped triton filter, removed laterals,examined no problem. Changed sand for coarser grade, no change.Tried a layer of stones at base of filter. Stripped multifuntion valve, replaced seals and gaskets.Once pump is running no more sand comes in. What or where to go next, any ideas please???

[Buggsw]

Are you sure it's sand? Or is it dirt. Sand lays in the bottom when you push it around, dirt will slurry up when you push it around with your brush.

Are you rinsing your multiport valve after backwashing?

If it's truly sand, then I suspect you still have a lateral or stand pipe that has a small crack.