Quote Originally Posted by mrdwkds View Post
but they have a pc. of paper on the wall that says they graduated from pool water chemistry school.
It looked impressive.

Don't be too impressed--somebody there may have graduated from pool water chemistry school, but they're also in business to make money. Besides, I find it odd that nobody that works at our local chain of pool stores actually owns or has ever taken care of a pool!!

But that's beside the point.........

I still think you have sand or other debris that's just settling out of the water, or that you have sand blowing into the pool. Even though your filter sand is white when it goes in, over the course of time and filtered "junk" it will darken and can appear brown/tan. Might be worth tearing down the filter again to check for lateral problems. Also, do you have a multiport valve that may need a new gasket?

When you run a set of tests tonight, check for free and total or free and combined chlorine. Also, if you'll test tonight after the sun goes down and test again in the morning before the sun hits the pool, that will tell you if there's something organic in the water--you'll lose more than 1 ppm. If you're not losing any chlorine, then you've just got debris in the water.

You'll do yourself a favor if you get that CYA off the bottom of your pool, either by vacuuming to waste or at least get it into the filter. Personally, I'd go to waste.

What hp rating is your pump?

Janet