I wouldn't let the chlorine drop, yet....just keep it up at about the 18 ppm mark until you're not losing any chlorine between sundown and sunup. AT that point, you can let it drop. If you added the stabilizer through the skimmer, it will take 4-5 days before it completely registers in the water, so I wouldn't bother to test for it or add more until then. However,--if you have to backwash the filter, you're going to lose whatever CYA is in there, so you'll have to start over and add more.

Nothing more you can really do except give it some time and POPP--Pool owner patience and persistence!! Remember that the chlorine is killing the algae, but the filter is what will take it out, and that's where your cloudiness is coming from. Watch your filter pressure and clean your filter as it indicates. It shouldn't be but another day or two of shocking before you can let your chlorine come down--and you can adjust your other numbers then.

Janet