As Ben indicated in his post above, test strips aren't really too accurate. We really need current water testing results taken with a drops-based kit. Do yourself a favor and get that Taylor K-2006 kit that Ben recommended AND in the meantime, pick up a cheap OTO/Phenol Red (red and yellow drops) kit. Your pH could be below 7.0 which is acidic and can damage your pool. We also need to know your CYA level which was done with the disappearing dot test to be able to recommend appropriate chlorine levels for this pool. Take a look at the Best Guess Chlorine Chart in my signature below. If your stabilizer (CYA) level truly is over 150, then you're going to need really high chlorine levels to kill this algae. And, the only way to measure those really high chlorine levels is with a FAS-DPD kit which is what the K-2006 is. Other test kits can't read high enough to help you.