I had an order of AlgaeBarn "clean" chaeto, and put it in a new 5g bucket with a fairly new pump and heater (that has never seen my display tank that had dinos). I also put a small light over the bucket. Anyway, I was trying to grow a bunch of chaeto while my tank was going through a dino problem, and once that was over, I was going to try to reintroduce the chaeto into my algea reactor. That was the plan. But I noticed that my bucket started growing dinos and was full blown dinos within a couple weeks in the bucket. OK, so a few possibilities: 1. The algaebarn chaeto came with dinos 2. There could possibly be contamination from my display tank? Not sure how, but I wasn't extra careful. 3. My RO/DI water has dinos, which seems impossibly silly (TDS 0, no measure of anything). The bucket was a fresh mix of Aquaforest Reef Salt and RO/DI water. I dosed Iron, Trisodium Phosphate, and Sodium Nitrate. I never "changed" the water, but topped it off with RO/DI every week (probably had some big salinity swings, but who cares, it's just chaeto). I dosed the three things just so the chaeto had something to eat. Anyway, not sure what the point of all this is, other than to report some interesting results. I wouldn't say it's absolutely the chaeto that I got my dinos from, but it does seem suspicious.