With a CYA of 110 or 150, you should definitely abandon the stabilized chlorine products. If you take a look at the Best Guess Chlorine Chart in one of our signatures above, you'll see the chlorine levels that you will need in your pool. You are also going to have to have the Taylor K-2006 or 2006C test kit as only that type of kit (FAS-DPD) can measure chlorine levels higher than 5. Your maintenance chlorine levels are going to be 8-15ppm and your shock level is going to be 25ppm. No wonder you have algae! You have not been keeping high enough chlorine levels for that high CYA. (You said above that you were able to keep the algae away whenever you kept your chlorine at least 8ppm. Now you know why!)

In your pool, each gallon of plain, unscented 6% bleach will add 5ppm of chlorine. Until you get a good kit, you can force your test kit to read higher by using a dilution method described here: Testing Without a Good Kit This is not meant to replace getting a good kit; it is just a temporary measure until you get the kit.

Test each evening and add enough bleach to get back to 25ppm. Continue to do this until you can go from sundown one evening to within two hours of sunrise the next day without losing more than 1 ppm. Run your pump 24/7 and clean the filter as needed.

You can order the kit through the test kit page in our signatures.