Good morning to all. Something is going wrong with my tank apart of high Alk. A week ago I decide to change the dose of ATI Essentials Pro of 4ml once a day to 2ml twice a day so went I setup the doser on/off twice but didn't choose off on the last drop on the app dumping overnight almost half of the bottle #1. After I came from work I saw a couple of corals not fully open and my red cleaner shrimp dead. I went and did an alk check with hanna and Its read 20.0 then did another test and came out the same, and by the manual means is out of range. Then I start doing a couple of w/c to bring down that number but instead of RSCP salt I got Aquaforest salt that a new batch seat at around 8dkh. Corals get a little better but then again start residing and I just loss the other cleaner shrimp. Yesterday night did a ammonia, nitrites, nitrates test and shows 0,0, 5ppm. I check my water and it shows 0 tds. Something that I saw yesterday was a light green film on the glass. I was thinking to get at least 40g of water from the LFS and do W/C to see if anything wrong with the water on a effort to bring everything back to normal. I have a 40g breeder tank with 35lbs of rocks running for almost two years, a 30g sump with about 15g water and a few rocks and cheato in the refugium and a skimmer. Also filter cup with some carbon and filter flosh that I change every two days. All fish are doing fine. Alk still reading 20.0 and its a new reagent that I already test before. Any suggestions will be gladly appreciated. #reefsquad