Yesterday I installed a new UV sterilizer and this morning all 6 fish are gasping air on the sandbed. 2 clowns, 2 flasher wrasses, flame hawk and tailspot blenny. Most of the snails were upside down and struggling. This is absolutely horrible. Ammonia is 0. Salinity hasn't changed. I'm currently making 10 gallons of saltwater, it's mixing/heating as I am typing and I plan on pulling the fish out and putting them in a QT tank. The UV is a Lifegard Aquatics 25w with a dedicated pump that I plumbed to pull water from the skimmer section and dump in the return pump section, running at 400 gph. I immediately turned off the UV this morning, that was about 1 hour ago and one of the clowns seems to be doing better since. I am thinking there must have been some chemicals in the UV or pump that got into the tank water. I wiped them both down with a wet towel before installing but didn't completely rinse them and now I am wishing I would have. I feel like I am about to have a heart attack Any other thoughts? Thanks. Tank is 5 months old and 57 gallons.