Hi, and welcome to the forum!!

If you run the SWCG for only 4 hours daily, and don't have any stabilizer in the water to protect it from the sun, you're basically going without chlorine for 19 or so hours of the day, which is why your pool turned green. Generally, we recommend that people get their water balanced without the SWCG, and then turn the SWCG on for maintenance. It can't generate enough chlorine fast enough to "shock" the pool to clear up an algae bloom, so all you're doing is wasting cell life by using an SWCG on a green pool.

So...if your pool is 22 ft diameter, assuming a 48" water depth, I'm calculating 11,400 gallons. In that much water, each gallon of 6% bleach you add will raise your FC by 5.3 ppm. Assuming no stabilizer, you need to add enough bleach to get your FC up to 12-15 ppm, and then hold it there until the pool clears by testing your water and adding more bleach as often as you can, but at least 2-3 times daily. To do this, you need a way to test the water without depending on the pool store to do it for you. Do yourself a favor and order a good kit (we strongly recommend the K-2006 you can find in the link in my sig). Until then, check your WalMart and see if they have any more of the hth 6-way drop kits. At a minimum, at least pick up one of the cheapie OTO kits (uses red and yellow drops for pH and Cl) and test your water with that.

Leave the SWCG off during the process, get the pool shocked, run a set of test results on your water and post them here, and we can help you go from there! An algae bloom isn't that hard to clear up, but the longer you put it off, the more bleach and time it will take.

Welcome to the forum!