Using citric acid to wash the gyre and the return nozzles, and I'm noticing that they get dusted with brown growth more than anywhere else in the tank. I've seen both dinos and diatoms on them by microscopy. Just wondering if the citric acid baths make the plastic a more hospitable environment, because I didn't have this problem before--problem was always too much coraline. Of course, new tank, new problems, so who knows?
