The way to tell for sure is to measure your chlorine at night and again in the morning, and make sure you're not still losing chlorine to something in the water. However, if you're sure that all the green is out, and you've thoroughly brushed the pool to make sure there's none hiding in ladder steps, light niches, etc, then you can let the chlorine level come back down--but you need an accurate CYA number to know how far down you can let it drift. If your CYA is actually 90 ppm, then you need to not ever let it get below 5, and you really need to keep it closer to 7-8 ppm. If you let it come down below that, you're going to have algae growing again (see the best guess chlorine chart linked in my sig for more info and the chart).

The chlorine you put in the pool killed the algae, now it's the filter that's going to remove the dead algae from the pool and clear up the cloudiness. Keep your filter running 24/7, cleaning the filter each time your pressure rises 6-8 psi over your "clean" pressure.