If it hasn't gone away in 3 weeks I'm afraid you're wasting your time trying to get it to dissolve. If it was going to, it would have by now.

If it's fine enough to go through a sand filter I'd put a sock in the skimmer and see if it'd catch it.

How old is your sand? Mabe add a bit of de to your filter or just bite the bullet and vac to waste.

Followup to my situation. I'm now wondering if this substance could be something else? I mean, it seems to be built up around the edges of the pool everywhere. Could it be something else like calcium? Should I run some tests to determine anything? Could it be sand coming out of the filter? Might try one more round of suggestions before doing a complete vac to waste.

And Titan, the sand is probably 3-4 years old, as is the filter.

Thanks guys.

Without a full set of test results and how you got them, we're pretty much at our ropes end with suggesting anything. Anything else will just be conjecture and woudn't be prudent.

Anything that doesn't dissolve after 4 or 5 weeks needs to be gotten rid of.

+1