No, that was definitely bacteria growth. I had to just clean my reactor and start over myself.
how often have you had to clean it in the past? It seems to be every 6 months for me and the whole cleaning is about a 1.5 hr maintenance job.
is it normal? Maybe it is and it’s just a con of running a SD but I seem to have read that people run theirs for years without any issue. Low maintenance was one of the reasons I went with a SD vs keeping a refugium or carbon dosing, which I regarded as more work.