Could this be algae or dirt/pollen?

[itstoohot]

I'm getting mixed feelings about this. We have had this show up in the pool. I shocked (with granular chlorine) and the chlorine level maintained somewhere between 5-10 the following day (using test strip). The pool company said I needed to brush the stuff off the floor to "meet" the chlorine, which I did. Still got the same chlorine reading the following morning.

The pictures posted are after we returned from a short vacation. The entire pool floor was covered. Assuming it was algae, I turned off the filter and triple shocked and brushed the entire pool floor. The following morning, I tested the chlorine and it was at least 10ppm (test strip doesn't go any higher). Now I'm back to thinking it's only dirt/pollen, so I started the filter and poured in clarifier. That was 2 days ago. The water is now dirty and cloudy and I can't see the deep end drain.

Specifics, if you need them (chemicals based on closest color test strip):
30,000 gal in ground vinyl liner
PH - 7.8
Alkalinity - 120
Total & Free Chlorine - 10 or above
Cyanuric Acid/Conditioner - between 50 and 100

Thanks so much for your help,
David