We switched from regular tap water...used for 7 years...actually had no big issues except alk would drop quickly and cal. never wanted to stay as high as I wanted it.........anyway we switched to a new 120 gallon. We now are using ro/di water. Added probably 80 gallons or so of new water to it last week, but the salt we normally use is Instant Ocean. We had left over IO, Oceanic, and reef that hubby combined in the bucket. My tests are showing up cal - 580 alk 12 mag 1580 Amm. 0 Nitrates 10 sg is a bit high at 1.28 and we are slowly lowering it to 1.25 w/ new refractomoter. I'm just not sure why cal and alk and mag is so high is it a mixture of the salts we had? Do I leave it w/ no water change and see if they drop? I have new tank, so no coraline algae sucking it out. I have fish, lps, softies. Everything looks "ok" , but due to mishap during moving them almost lost EVERYTHING. Only lost one shrimp and LG Sailfin we'd have for 5 years. Corals that looked bad seem to be opening up and looking better. (thought we'd loose them for sure, but actually the frogspawn and hammer is closing their mouths now which surprised me).