If your pool is green -- you have an algae problem.

If your pool is cloudy white and doesn't not turn green when you brush, and you can't hold chlorine overnight . . . you have a DIFFERENT problem.

Either way, getting chlorine to hold overnight is a key first step. But, I want to avoid massive doses that might temporarily be high enough to bleach your liner. So, until you have a good kit and have given us test results, I'd recommend sticking with the doses I suggested.