Just my opinion, but I think that the ventures built into power heads are so pathetic in most cases that it isn't going to do
anything except increase salt spray. If your dissolved oxygen is your goal, I would find a different way to do it.
To answer your question, you probably can't over oxygenate the water.
TF - I agree with Doug, I tried this method myself once when i started w/ my first marine aquarium. I didn't have a test kit to see how much benefit it may have had, but I can guarantee you one thing: it makes one helluva mess with all the salt spray you're going to get. there are a few options though. 1. just point the powerhead(s) so they disrupt the surface of the water significantly. 2. (better idea in my opinion) Get a decent skimmer. for one thing, this will remove alot of (I guess not all, but hey, what more can you ask for? hehe) the nasty stuff, plus it'll give you all the O2 in your water that you'll need. HTH,
wife: "What's it going to cost THIS time?"
yeah, I know what you mean with the salt spray. I actually changed the setup and have the 802 running the uv and use the RIO 2100
for water movement and when you open he aeration all the way it blasts big time. But the tank fills with bubbles and its not pleasing to the eye. I actually have a skimmer but will need to upgrade it with the larger tank.