I keep a batch of chaeto in a QT where there is no nutreints for it. YOu can see it lighten up over time, so what I do is periodically thin out the chaeto in my fuges, and throw the harvested chaeto into the QT tank, or another tank that is unused. I do swap out chaeto from the QT or unused tank with chaeto in the fuge from time to time, but normally have never found that dark green or black looking chaeto was any less effective in removing nitrates. As it gets more and more nitrate nurishment it simply propagates into more chaeto. I have also found that it does the chaeto no harm to rinse it under fresh rodi water or even reg tap water, to rid it of debri etc that accumulates in it. Yes it may kill any pods or mini dusters but its the chaeto thatI am wanting anyhow so what little other critters die off is no big deal. I use chaeto in the hob fuges made out of AC10 / 500 filts and they always collect a lot of debri in the chaeto, so its nice to be able to rinse it nice and clean periodically just like clenaing a filter pad with fresh water, shake it dry, and throw in QT or back in fuge. Do not keep light on the chaeto any longer than perhaps 10-12 hours a day. You will find it does need a rest period like anyhtng else requires, and 10 or even 8 hours a day is sufficient with 12 hours being about the max to give it. My cheato just about doubles in size every 3 to 4 weeks or so.
