Slamming for 9 days, am i done??

[Coolcat]

24' round ABG, SWG, Ontario Canada.
I started opening late this year due to logistics and started with some green soup due a warm spring.
Last night topped up chlorine at 9pm. Reading at 10:30pm 13 FC, 0CC, 34 CYA.
Today at 5am 12 FC, 0.5 CC
Water is clear.
I feel like I am done.... however after vacuuming to waste yesterday 1 hr later I have dust on the floor. I think it could be sand. But I want to rule out the algae first.
2nd year with this house and pool, still learning, haven't opened up the sand filter yet.
I had the same problem last year which I thought was algae. Maybe it's been sand all along.

 

[Texas Splash]

You passed the theOvernight Chlorine Loss Test and other SLAM criteria, so technically you are done. See if you can grab some of that stuff. Sand should be gritty and some of it near the return jets.

 

[Coolcat]

We have a centre floor drain as well as skimmer. The dust gathers around the middle and anywhere there are seams or wrinkles in the liner. Should it always accumulate around the jet?