Hi, I am on my 3rd day of SLAMming my pool for mustard algae, I have a question regarding the CYA. I am reading so many conflicting ways to properly test for CYA. One site says do it in direct sunlight, another says back to sun, do it at waist level, donít do it at waist level, etc.. Can someone please tell me the proper way to test. When I first started slamming my CYA reading in sunlight was 25, this was 3 days ago so Iíve been shocking to 12ppm, I tested today on a very cloudy day with no sunshine and after some rain last night, and I am now getting a CYA reading of 40, if this is correct I should be shocking at 16ppm and not 12. When I check on pool in the mornings water is blue, but when I go to sweep I am sweeping green off the floors into the deep end even after day 3 of slamming, the nice blue in the deep turns ugly green after sweeping, now I must admit it is getting somewhat better with each day but it is still green. I have been sweeping 2x per day, backwashing, and checking on FC levels in the morning and late evening and adjusting to 12ppm (It has been dropping to 8-9 and then I add to get back to 12). Is this normal to still see so much green after sweeping on day 3? I know it's a process but I thought I would stop seeing the green at this point. I'm thinking it may be because the CYA is not what I originally thoughta and not shocking high enough. Please help!