I want you IO salt. Last 4 pails have all been around 840 in mag

This has always been my readings as well.

Most of my pails of IO have tested calcium 380 ppm, alkalinity 11 dKH, magnesium 1150 ppm for years. I went through 4 pails of H2Ocean and it was 400, 8, 1200. That's using Elos for calcium and alkalinity, Salifert for magnesium.

Thanks for the replies guys... I think I'll go see if the only pet store in town has any IO... likely the best chance of finding it.

For the lowest magnesium in salt I have used was ATI. I think it was around 600-700 . I don't see it available in most LFS though.