I was having a terrible time with my 75g and trying to get rid of the very heavy green water it had. It was so bad the it tinted my filters green and there was only about 2 inches of visibility into the tank. But 3 days ago I bought a UV sterilizer to help clean my tank... best purchase of my life! after 3 days I did another water change and, BAM! my water is almost perfectly clear! I can actually see the back and my fish again
I would definitely recommend this to anyone dealing with green water, it is incredible how well it works and it definitely lives up to its reputation

