I noticed yesterday that our small, in-ground, 5K gal, gunite pool started turning from clear blue to a clear aqua color and there seems to be yellowish stains on parts of the sides and steps. I tried brushing it, but it doesn't react like algae and brush away. It seems more like a pale stain (similar to metal stains I would occasionally get in a previous pool). I had a sample tested today at our local pool store:
I had added 1/2 # of shock, replaced the two 3" chlorine tabls as well as some stabilizer because it seems the chlorine level would go from 5.0 to non-existant in a day during the past week. so, I wasn't surprised that the chlorine and stabilizer levels were high. I was told to remove the 3" chlorine tabs from the pool, and then add 6# of alkalinity increaser. A couple hours later I was to add 8 oz pH plus. I did as directed and now it seems like the pool is getting a bit more cloudy. I also drained about 3 inches of water and am currently adding more water to try to bring down the chlorine level. The guy at the pool store wasn't very helpful when I asked about what might cause the sudden change. Any help or insight you can provide would be greatly appreciated.