You instincts are excellent. If "Megashock" is $2.49 a gallon, buy me 10 cases!!! In my area 12.5 liquid chlorine (that's what it is) runs $4 gallon. 1 gallon is the equal of 2 gallons of Ultra Bleach--at $1.75 per gallon is pretty good. Actually, 12.5% breaks down to lower strength quickly so you want to get it "fresh" and use it up, or store it in a cool, dark, dry place.

Don't be disgusted--you are making excellent progress because you are doing the right thing (other than the algaecide)--lots and lots of chlorine and clearing the sludge out of the pool.

You noticed that the heavy dosing really killed a lot of algae--that's what you need.

You need more of what you got: Chlorine, Patience and Persistence!