Why is my pool green even after treatment?

This issue is likely due to overstabilisation, or a chlorine lock, which results from overuse of stabilised chlorine products. Your stabiliser levels are out of balance and need to be tested. If the level is higher than 100 parts per million, you will need to drain 30% to 50% of your pool, which requires setting your pump to ‘waste’, following which it will require refilling. Make sure that your new stabiliser level is between 40 and 80 parts per million. You should also then test the pH of your pool and apply shock treatment. Alternatively, get in touch with your local Pool Xpert and we’ll talk you through what we can do to help.