Watermom's given you the prescription--I just wanted to add that the Yellow Out, Banish, and all the algaecide you added have created a really big chlorine demand by themselves, and that combined with the high CYA is why your chlorine was not being at all effective against the algae. Algaecides are much better at preventing algae than actually killing an active bloom, but even then we only recommend Polyquat 60. The othe algaecides can cause all sorts of problems including foaming, copper staining, and breakdown into ammonia, which creates an even bigger chlorine demand.

So...like Watermom said, don't put anything else in there but chlorine--no trichlor or dichlor--and get that chlorine up to 25 ppm and keep it there until the algae is dead and you stop losing chlorine overnight. Keep the filter running, and keep an eye on the pressure--backwash it as necessary. It will clear up--but again, the key to keeping it clear is to never let your chlorine drop below 8 ppm. (or even better, drain/refill part of the water to get that CYA down)

Janet