Ok guess ill chime in real quick since people are mentioning trying Kent and that's what I use. I'm at 13 months of Kent reef salt and I've had maybe 1/10 mixes end up with the Brown residue. Same batch of salt yet I've seen different results in the end and also as with everyone else this IS 0tds water. The top off container has never had this brown residue so I agree the water is not the issue. Imo
, although don't know how much its worth on the subject lol. I believe that its how the salt has been mixed. The reason I say this is because I know that calcium precipitation can happen when alk
climbs to fast so maybe something like the iron needs so much buffer before the water can properly hold it.