Sand/dirt in pool

[mixman98]

How's it goin' everyone? I'm a newbie on this site, but already have learned a lot from all of the info on here. I have an 18' round pool with a Hayward 166T sand filter. The pool and filtration system was purchased new in 2006. This is the first time I had a filtration problem. The dealer I purchased the pool from replaced the spider gasket for the multi-valve and that did not cure the problem. So I then removed the sand and inspected the laterals. I did not see any cracks in any of the laterals but 4 of them had a good bit of sand in them so I replaced those 4 and also added new sand while I had the filter empty. So after backwashing the new sand and flushing the system, I still have the same problem. I just ordered the other 6 laterals. If this does not cure my problem, what else could it be? Thanks
Larry

[Swim Today]

If sand is getting back into the pool there is a crack somewhere in one of the parts. The good thing is with sand filters there are not alot of parts to look at. The laterals are the most common parts to get damaged. Did you also inspect the stand pipe (the part the laterals are attached to) for any damage? Check the bottom part of the valve head for any cracks. When the new sand is getting added are you making sure none goes down the stand pipe by covering the opening. Also when adding the sand are you making sure there is enough water in the filter tank to cover the laterals with to protect them from the new sand being poured in. The water acts as a shock absorber for the laterals against the falling sand which can cause a damaged lateral as you are refilling the tank and not know it.