No color to me. Just dark bacteria slime/film. This is after a year of keeping water mixed all the time. I don’t feel a need to clean it out, but might now that I know there’s a little funk. I was having a crazy white/tan film from RC that was just ridiculous. This is growth from my container, not from the salt imo. Big big difference. The RC clay is obviously a result of the salt and I felt the need to clean it after the first half bucket.
I’ve used a lot of salts as I worked in the industry for a while. Not the newer salts but I would buy whatever was cheapest (between a few trusted brands at the time) for store use, but I always came back to Tropic Marin for its easy mixing, balanced elements, and obvious to me results. Other salts were fine but TM was superior and a “you get what you pay for” type of product to me. This still holds true to this day. Now if I still ran a store or a farm or had a larger system I was having to replace a lot of water there would be a point where I’d compromise on quality for a less expensive product. Feel like IO or RC always for that bill fit that for me, cheap readily available and consistent. In my personal tank I prefer TM.