air/water exchange

[donm]

Is it better to have a spray bar above the water line spraying water onto the surface of the water or have it submerged directly under the surface of the water?
I just saw one at a lfs that was submerged. It looked like it added to the water movement in the tank a little bit more then a spray bar above the water line. It would greatly help me out if I could do this because the spray is creating algea on my hood cover and is at times it is a bit loud.
Thanks for any input....

 

[broomer5]

Submerge it, but keep the water jet near the surface.
This way it will reduce salt spray, increase circulation as you mentioned, reduce the noise and cause some surface agitation for O2 & CO2 gas exchange as well.