Filter flow and breaking surface tension.

[tate8]

I have 2 AC50s on my 36 gallon bow front. I made water baffles from plastic water bottles to keep the current down from the incoming waterfall. It does a really good job and my water is very calm.

With this set up, am I breaking the surface tension of the water?

I have recently removed my air stones and pump and started thinking that I might be suffocating my fish.

Here is a video of the setup.

[Orion5]

I think that you'll be fine. Breaking the surface tension of the water doesn't necessarily mean there is more oxygen exchange. Agitation of the surface will increase O2 in the water (i.e. if you let the AC filters "ripple" the surface of the water, this will increase the oxygen exchange). Other people may have more to say on this... but I would suggest just leave it as it is and if you notice anything strange, restart the airstone or better yet, let the current flow from one of your ACs. Hope this helps!

[Northerly]

Were the filters disturbing your substrate or something? By the looks of it you should be ok, but I personally like to have a bit more surface agitation. As stated, don't worry unless you see fish "breathing heavily", seemingly gasping for air. If you notice anything like this, or anything else that seems odd, I'd throw the airstones back in or slacken the baffles a bit for more flow. Airstones are usually not necessary with HOB filters though(especially with such adequate filtration), and I think you should be fine.

[Dennis Bissett]

Agree with Northerly, looks ok, keep an eye on the fish, if they start going to the surface more often its an indication they are looking for air

[tate8]

The current did nothing to my tank. I noticed that when my Harleys would swim through it the current would push them down. It seems with the baffles installed that my fish go to the upper part of the tank more.

[Lady Hobbs]

I fill my tanks right to the top so I like to have a bit more oxygen. I just think fish are more active with a bit more going on. My Harleys are in a 29 gallon with a Cascade 300 and a small Whisper on their tank. (The Whisper is there just to remain cycled for when I use the quarantine tank.)
I have a good flow going on and the Harleys have no problem with it. Some fish actually like it.

But they will let you know if it isn't enough flow and will start remaining at the top of the tank.

[Amelia]

My Harleys love current and always try to swim up the filter outlet in my 45g. Occasionally one will get halfway up before being spat back out, as it's only a wet-do-dry trickle system system and isn't hugely powerful.

[Lady Hobbs]

They like it or they would not swim there. When I had rainbows, they would sit right in the largest current, get knocked backwards and kept going back for more.

You want enough current to move the stuff around on the bottom of the tank.

[tate8]

Thanks everyone. I took the baffles off.