Vacuuming dirt right back into pool

[Cara]

Ok, I have read a few threads in here that mention my problem, but I can't seem to figure out a solution. We have a Hayward super pump and Hayward sand filter. When we start to vacuum all seems ok, but within a minute or 2 the dirty water starts to come back into the pool thru the return valves. Does this really mean that the sand in the filter needs replacing? I figure it's about 8 years old. Does sand really break down? The stuff we are vacuuming out looks like dead algae and is really light, when you push on it with the vacuum head it turns into a cloud. Could it be too small of particles and just passing thru the filter? Although sometimes it's larger chunks that come back out.

[muss08]

It could be very fine particles passing through the sand. When was the last time your sand was changed? I have clients who havent changed sand in 10+ years. The sand itself will not break down. The sand catches debris on its usually rough edges. Over time oils, grease, and scale will make the sand smoother reducing efficiency. Get a sand filter cleaner/degreaser. The cleaner should take care of BOTH scale and grease. Try this before replacing sand. Have you had any sand coming out of the returns? If sand is escaping this is a broken lateral. You can also try putting in just enough DE to raise your pressure 1psi and this will help the filter catch smaller debris.

[Cara]

Thanks, I will definitly try that, sounds better than replacing the sand. But if all else fails then I will replace it. We just bought this house so I really have no idea what kind of upkeep on the pool equipment has been done...although, there are some spots around the backyard that have a fair amount of sand in them that makes me wonder if it has been done before. If I get this cleaner and it doesn't help, can you tell by looking at the sand that it needs replacing.

[Cara]

Ok, here's what I ended up doing...vacuumed with multiple backwashes and rinses, then I put a nylon over my skimmer basket. Voila! It caught all the little fine particles and my pool is now spotless!