Increasing gas exchange without an airstone?

[Plec123]

I've got a 38 gallon planted setup with a 75 being put together slowly. Running a fluval 406 for filtration and will upgrade to an FX6 with the tank upgrade. Also, there's a glass hod on the tank covering almost all of the surface with about a half inch to an inch of open air between the hood and the water.

I've noticed over the last few months that occasionally my plecos are all breathing very quickly, and I feel like this is probably due to low oxygen levels. (They're all small species, please no one get on me for overstocking.) I recently bought an air pump/stone to disrupt the surface and increase gas exchange, but the bubbles are unsightly and I can't stand listening to the pump while I'm watching tv 10 feet away.

Would raising the filter output to make some small waves in the surface cause much of an increase in gas exchange? Or does anyone have any better ideas?

 

[Chefken]

Breaking the surface is key! I use the outputs from my Fx6 and fx4 plus a huge wavemaker to ripple the surface. i also found the airpumps annoying in my living room and the water spots destroy my glass lids. My 180 gallon is stocked pretty full and has no issues.

 

[Ulu]

Get a stronger filter pump and a louder TV!

Plecos are little poop machines and they grow quickly. It's hard to change the water often enough to keep them super healthy.

 

[LBDave]

Breaking the surface is key! I use the outputs from my Fx6 and fx4 plus a huge wavemaker to ripple the surface. i also found the airpumps annoying in my living room and the water spots destroy my glass lids. My 180 gallon is stocked pretty full and has no issues.

I hate airstones. Good wave action at the top (filter pump or wave pump) should work I would think. Airstone alone may not be moving surface water enough.

 

[Plec123]

Thanks all! I'll try raising the filter output and getting some waves going that way.

 

[islandguy11]

Don't forget that water movement at the bottom of tank is also important if you really want to increase oxidation -- hence 1 reason why I actually like air stones as they also help circulation by lifting water from the bottom of tank to the top (though I run bare bottom and not natural style tanks so my perspective is likely different on the aesthetic part).

If you didn't want to use an air stone you might consider to get a small mini-pump that you can hide behind a rock or plants and aim it toward the top of your tank; it'll help with both circulation and surface agitation.

 

[Coryloach]

Don't forget that water movement at the bottom of tank is also important

Very true. Aquarium substrate acts as a giant nitrification engine(and more) when the tank is well oxygenated and water flow reaches the bottom to replenish the surface layer of the substrate with oxygen.

In tanks with bad flow and no sufficient surface agitation for oxygen exchange one also gets bad substrate subjected to predominantly anaerobic decomposition, beaming with unwanted pathogens, and producing ammonia instead of taking it up, and also producing harmful gasses and other bio-products of the same harmful kind.

I find that the best way to set the flow in a fresh water tank is to create a circular flow movement, for all different reasons. Technically, in terms of external filters for example, that means having spraybars along the back long side of the tank, water hitting the front glass, or spraybars the short side of the tank blowing against the opposite side. All outlets must flow in the same direction(no water cross over). The water then makes a complete sweep front to back or side to side, so the actual inlets should be on the same side as the outlets.