I'm not relying on it for anything right now, since I have already set my bubble rate to get the green color. So, I am just leaving it in the tank out of lazyness right now. If I wanted to rely on it again I would change the solution in it. Like any other object in the tank this begins to get "biofilm" growing on it too, so it needs to be cleaned periodically. Mine is in a very low light corner of the side glass, so the growth of "biofilm" (sounds so much better than algae) on it isn't bad at all yet.