[quote=Unabomber007]I can post full numbers when I get home later, but from memory:

Stabilizer: 60
Chlorine: 5
With a CYA of 60 you need to be keepingh the chlorine between 5 and 10 ppm. If it hasn't been kept consistently at or above 5 ppm that is very likely why you have the algae.

The only thing that's kinda high is pH which is at 8.2
A high pH will exacerbate the low chlorine level.

If I were to vacuum to waste, it would probably take a week to do so as the water level would go down and down and down with vacuuming. I shouldn't have to do this as I could vacuum my pool on my old DE filter with 6 inches of muck and never have any filtration problems, the water always came out clear as a bell from the returns. I only cleaned my DE filters once a year and then only for fun to remember the process.

Last year w/ DE filter = wonderful pool
This year w/ sand fitler = I want to fill it in

The issue is NOT with chemicals, that I'm sure as I have a wonderful test set and am a chemical nazi. I'm not sure if the green stuff is algae or is some weird crud the sand filter is spewing out. I assume it's NOT algae since my leves are and always have been fine since finding this site.
I think you're prematurely ruling out the most likely cause of the problem; insufficient chlorination. There are many people here using sand filters who don't have any of the problems you're describing.

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If you don't indeed have algae, the problem may be with your filter but the eastiest and cheapest first step woould be to bring your chlorine to shock level (>= 20 ppm for your CYA level) for a few days or until the water clears and you can hold the FC level overnight. If that doesn't work, I'd open up the filter and inspect for the proper amount and type of sand (filter sand is vey fine).

By the way, have you talked with the guys who installed the filter about the problem?

Best of luck.