What is this brown stuff on my salt mix?

[kevensquint]

Hi I have a 30 gallon plastic drum fed by RO/DI ( 0 tds) I have been switching salt brands over the past year depending on availability. My last 2 batch mixes were with Brightwell Neomarin. From only 2 30 gallon fresh batches of SW my barril was filthy with a brown fluffy residue. Here is the last 8" of water from the barril after wiping it down. That cannot be good for SPS. Ironically I have been battling random RTN for the past month.

 

[Doctorgori]

gheez, sure that wasn’t Reef Crystals?.... man I got nothing, yuck

 

[Jseimo]

I’m no expert. But i wonder if the different binders and anti caking used caused a chemistry experiment in your mixing buckets. I know you said depending on availability, but consistency is key

 

[Uncle99]

Wow, that’s certainly a concern IMM.
I’ve seen beige water but not brown.