Green pool water remedies
If your pool water turns green, this could be caused by algae growth if the pH is too high or if the chlorine level is too low. Adding chlorine tablets (sanitizer) should alleviate this. If the pH remains high then add ‘pH decreaser’ or ‘pH down’ and follow the instruction on how to apply.
If the pH is low and the chlorine is 3.0 ppm and the water remains green, then this could be an indication that your water has a high copper level. First, try adding baking soda to balance the pH. If the pH and alkalinity are in the normal range, then you may need to add a liquid conditioner which puts a film on your filter to trap the fine copper particals. To be certain it is a copper problem, have your water tested at the pool store.
Green water could also be an indication your filters are dirty or coated with tree pollen. This usually happens a day or two after you add shock because it breaks down the yellow/green pollen material collected on your filter that is eventually pushed back into pool.
To remedy this, pull the filters and hose them off. Sprinkle baking soda around the pool and within a day or two the water should be clear.
For more info on how to maintain swimming pool water, go to water quality.