Our pool of 17000 litres with sand filter has a fine sediment deposit of milky colour that settles but is too fine to be filtered even after adding floculant. It clouds up on vacuuming. PH & chlorine are correct (7.4 & 1.5). So we are now vacuuming to waste into a cube, waiting for it to settle then pumping clean water back but still losing loads of water. Had the same problem last year & have been advised to keep adding floculant at great expense. Any ideas what causes this & how to fix it.
Paul