This salt may be alright but I have had problems with Seachem salt in the past. It never mixes clear, I have tried several different methods. The last 2 buckets I got may have been out of the same batch, but they were very low in mag. I checked with 2 different mag test kits and it was just about 800ppm. It took me the better part of 2 gallons of Kent Super M to get the Mag right with those 2 buckets of salt. Super M is not cheap in those quantities! I have switched to Reef Crystals and have found it to be much more consistant. I think Seachem has some quality control issues going on with their salt. If you factor in the cost of my Super-M, it cost me $75 per bucket. I know now they are suppose to be testing this new salt before they send it out, but shouldn't this have been happening all along?