I changed out my cartridge on my sta-rite 450sq/ft last weekend. The filter was not cleaned when the pool company closed my hot tub in December last year and was in a black garbage bag until I just cleaned it. We close our pool end of September and keep the hut tub open until Dec. I hosed it down but evedently not enough. My pool clouded up so I shocked it and it cleared after 3 days and passed the over night test of not losing 1ppm FC. The pool is about 10 years old and this is our third season in this house. We have our pool drained in the spring and power/acid washed before opening. As the season goes on we are getting spotty gray discoloring and it really came back this year after I shocked. I have a Nature2 filter and I just removed it after reading other posts. Could this be the cause? My CH seems alright see the test results below. Also we plan on having our hot tub replaster next spring. The pool guy says they can buff the pool surface to get a new surface exposed. Has anyone had a good experience doing this. Please let me know what you think is causing the discoloring and is there anything I can do to get rid of it. It doesn't brush off. (attached photo look at middle bottom, top left and right is a reflection).
Thank You in Advance!