ggrowney said:On another post, someone said no.
It cleared it up for me and also in my daughter's coldwater tank. I'm not about to offer a guarantee, as I have nothing to gain by it, but I know it works. It can take several days for all the water to circulate through the device, depending on tank size, unit size, and flow rate of the powerhead or power filter running it. If you don't want the expense just cut feeding and remove all decomposing matter and the overpopulation of bacteria causing the bloom will eventually die off, giving you clear water again. The UV Sterilizer just kills it quicker, bit it's the same thing.