Hi, I bought a bucket of Coralife salt yesterday and got a free T-shirt inside. I happened on a Newsletter inside the bucket. In it is an article by Bob Fenner concerning the danger of using freshly mixed saltwater with high concentration of dissolved oxygen. He said that high O2 content of the water may actually harm the fishes, causing gas-bubble emphysematosis. This is manifested by an acute bulging of both eyes (acute bilateral pop-eye). While there are other causes of pop-eye, this condition differs in that the time of onset is rapid, both eyes are affected and more than one fish are affected usually a few hours after a water changes. In extreme cases, gas bubbles may be seen stuck on fishes' scales. He added (and I agree) that if only one eye, one fish, and it occurs over a period of several days to weeks, other causes should be sought such as parasites, bacterial infections, or nutritional defficiency.
I just want to share this info in connection to aerating water. In essence, letting it stand for a day or two to let dissolved oxygen diffuse to the surrounding air. Happy reefing everyone.