Absolutely agree with Don.
I attribute it to directly saving my sps tank when a series of events started a catastrophic colapse of the water quality. SPS tank that was packed with large fish and other softy and LPS corals.
Took three months, but saved most. The Ozone was the biggest part of the final cure. Lot of work, or time, or money to buy equipment, but if you need it and have it, you'll love it. Not for beginners or low budget systems but awesome.
Even if you do not currently "need it", sure makes an excellent insurance policy against unforseen future problems.