This is the problem I'm having with instant ocean. I might just try that with the IO that I have left then switch when its finished. I just tested IO and out of the bucket it was 11.2 dkh and 285 ppm Cal. Adding calcium chloride sounds like it would work, driving down the Alk while adding calcium as well..To alter the high alk of Instant Ocean I was adding calcium chloride which helped drive the alk level down in the newly mixed saltwater to comply with the lower Alk levels.
I tried that experiment yesterday with the Instant Ocean. I added a little calcium chloride to a gallon of IO salt water. The IO tested at 11 dkh before I added it. After the calcium was added the calcium ppm went up but the Alk stayed the same. The plan didn't work...
Totally agree,I don't see how the Dkh of the salt matters that much, considering how much people dose on a daily basis to maintain Dkh, it would make more sense to maintain a dosing scheme to achieve the Dkh you want.
Unless you are doing a huge water change it won't matter that much in my opinion.