My Instant Ocean salt mixes up to 9dkh at 1.025-1.026 salinity. Check the alkalinity of a fresh batch of saltwater after mixing for a few hours. Maybe you just have a bad batch of IO.I only have around 10 frags of lps and a toadstool, 4 frags of sps ( recently added) and water change weekly. I tested right after water change and it was 7.5 dkh, also at LFS it was 7.5dkh. What is causing my alk to go down if its not the salt? I will definitely test pre mix salt to see what dkh level at 1.25 salinity. I wanna stay around 8 dkh so it wont go lower than 7.5 dkh.