Problem with cloudy in-ground pool. Brown residue on liner.

[PoolDoc]

After I put the HTH clarifier in and ran the pump ovrnight the next morning the pool seemed clear but wth the residue on the liner. After putting in the Aquabot and running for awhile the water clouded up.

Sounds like the clarifier settled it out, but then the vacuum re-suspended it in the water. I'm guessing it's really NOT sand-like (heavy, sinks rapidly, can be felt as grainy) but more dust-like (not heavy, floats away if you create a current by waving your hand or pool brush, can NOT be felt as individual grains)

Questions:

1. Have you cleaned your filter this season (as in, took it apart and washed clean)? <= Forget this; I misread the chart, and thought you had a DE filter.
2. Do you have a manual vacuum, like this:

Poolmaster 27514 Classic Full View Triangular Vinyl Liner Vacuum @ Amazon OR
Poolmaster 27200 Premier Heavy-Duty Flexible Metal Handle Vacuum @ Amazon

Hydro Tools 8365 8- to 16-Foot Adjustable Fluted Premium Fluted Telescopic Pool Pole, White @ Amazon
Poolmaster 33430 Premium Vacuum Hose with Swivel Cuff, 30-Feet by 1-1/2-Inch @ Amazon

3. Do you have a multiport valve on your filter?
4. Is it light tan (ie, the color of dirty DE powder)? <= Forget this one, too.
5. Have you tested your filter with DE powder, to see if it 'leaks' dirt back into the pool? <= New question