I painted my pool this year with epoxy paint and cannot keep the chlorine level up. I put in 25,000 gals of city water and I thought opening the pool this year would be a easier this year. I did the chlorine drop test and brought the chlorine level up to 15 and tested it for around 8 hours and it was at 15 at the last test around 10:00PM. When I tested it the next morning it was back down to 0. Where do I go from here? Water is crystal clear.