The black (burn) marks show up on Gray plaster pools. White plaster pools will show up as a yellow or rust color. Remove the tabs and put them in a proper floating devise, the marks will go away in time.
Try using wet and dry sand paper on the burn marks to reduce their visibility and roughened plaster.. additionally, tablets of any size should NEVER be placed or tossed into the pool or skimmer. K
Now you will have to scrub the walls and leave the filter running to get rid of the dead organic material. Chemicals only keep the organic material from growing, they do not get rid of it. But you do get to spend some time in the pool... scrubbing the dead organic material off the walls and bottom. Keep the chemical levels up and this won't happen again.
couldnt tell u without reading the bottle that the floc came in The idea of putting flocculant in the water is for the flocculant to attack to impurity's in the water and sink to the bottom of the pool, Ideally the water should not be disturbed while this is happening. After a couple of days of this you will note a cloudy area on the bottom of the pool. this should then be vacuumed to waste. You should not swim in a pool being treated with flocculant if you want the treatment to be totally effective. RB