I don't know what happened to IO, but I think it is becoming more and more regular to see inconsistant results with IO. I'm sure there are many that if testing would find their bag/bucket of IO to be well within normal parameters, but I have used 3 bags of IO over the last year that I have been back in the hobby, and every one has tested low in
CA and high in
ALK, to the extent that it has become common place for me to add calcium chloride to the new
SW, to raise
CA and deplete the
alk. I have no idea what the
Mg was, prior to getting my test kit on Mon. About 5-6 years ago when I worked for an
LFS, we tested several bags of IO, the
CA always came out between 370 and 400
ppm,, the
alk always measured in at 3.5-4.0 meq/L and the
Mg always measured between 900 and 1200
ppm. It was a very consistant salt. I suppose that with the boom of the
SW industry over that time period, quality control is not what it used to be
FWIW, I have switched to Tropic Marin, when I had my reef several years ago I used Reef Cystals (although this is made by the same people that make IO) and never had problems, and I have heard nothing but good things about Kent Salt.