Why inject air at night in a planted tank?

[lazzaroni]

Why is it necessary to use an air pump in planted tanks when the lights are off?

I am looking for ways to reduce clutter on my 50 gallon planted tank. I installed a Cal Aqua Labs inline diffuser on my Eheim 2128, which gave me better CO2 absorption and one less airline.

I would also like to get rid of the airline for the night time air pump, but I can't hook that up to the diffuser because it doesn't have enough pressure.

Can I just remove the air pump altogether? If I do need the night time air bubbles, should I get a second canister for compressed air and feed it into the inline diffuser at night? Or is there an air pump that is both quiet and strong enough for use with a ceramic diffuser?

Thanks!

 

[Philosophos]

You don't have to run air at night, but it's helpful. Personally I just rely on high surface agitation to gas off CO2. It's done because plants use exclusively chemical respiration at night, which means they're uptaking O2 rather than CO2.

You could try plumbing something in if you're the DIY type. Maybe a Y splitter, and airstone, and a little work tapering down?

What kind of filter are you using? Does it come with a venturi intake attachment?

-Philosophos

 

[lazzaroni]

Philosophos:

Plants absorb O2 at night? Does that mean that they produce CO2 as well?

If that were the case, I can see how things could get out of whack. Both the fish and the plants would be consuming O2 and producing CO2.

I am using an Eheim 2128. No venturi intake.

I intentionally have minimal surface agitation, but I also don't have any room in the cabinet for additional filter plumbing because the pipes are too stocky and the cabinet is too short.

That's why I was thinking about the second canister for compressed air. I was just going to try to pump air to the Cal Aqua Labs inline diffuser via a Y-splitter on the airline.

Thanks!

 

[lazzaroni]

I checked with my CO2 supplier. They supply "breathing air" in 10# cylinders. Same cylinder as CO2 and the air is $20.

Based on my CO2 cylinder use, I estimate I will get more than a year out of a 10# cylinder of air, and I can get rid of the noisy air pump.

Seems like a doable solution, that is, if I really need the air at night.

 

[Philosophos]

Ya, they put of CO2 as a result of their metabolization.

$20 is a ripoff; go to a dive shop and ask for a refill; it should be 1/10th the price.

-Philosophos

 

[lazzaroni]

Thanks for the suggestion!

I wonder how many people use compressed air in addition to compressed CO2.

 

[evandro.carrenho]

Injecting O2 at night was an effective way of removing surface scum in my case.

 

[lazzaroni]

Evandro, are you injecting straight O2 from a canister?

I started getting surface scum again after I pulled my night time air pump and stone.

 

[evandro.carrenho]

I use just an air pump and stone. It made a huge difference in maintaining a clean surface.

 

[Tom Barr]

I do this for my higher fish loads. Mostly for fish and to fluff up the plants, the sticky bubbles pull detritus and algae off the plant leaves.

Adds plenty of O2 for 14-16 hours per day, since I only add CO2 8-10hours at most.

A much better/cheap solution for O2 in line additions would be these:

Aqua Medic Reducing Tee

Obviously add a check valve!

Or for finer mist:


UP CO2 Atomizer System for Plant Aquarium 12/16mm Hose - eBay (item 370236770101 end time Oct-26-09 12:54:33 PDT)

Some use a heavy air stone and place it under the outflow from a filter.

Regards,
Tom Barr

 

[Tom Barr]

Thanks for the suggestion!

I wonder how many people use compressed air in addition to compressed CO2.

Compressed O2 or air really is a lot more involved/costly than simply using an air pump.

I could see adding O2 during the light period along with CO2 gas to push the levels of each up, to reduce fish respiration stress. But not at night.

Regards,
Tom Barr

 

[lazzaroni]

At first I wasn't able to use the Aqua Medic reducing tee because I didn't have enough room on the outflow pipe, but I might now. I would still much rather just pump air into the inline CO2 diffuser.

Any recommendations on an air pump that can push air through a CO2 diffuser?

Incidentally, the Cal Aqua inline diffuser is working beautifully. It has to be one of the most worthwhile changes I have made to my setup.

Thanks!

 

[Tom Barr]

I like the Cal lab stuff, a bit $$ but still lot cheaper than ADA.
The AM reducer really works pretty well.

the other thing is to simply have an aspirator smaller Rio powerhead etc at the surface that comes on at night, or a slow air fed power head lower down etc, anything to add air that's quiet and adds current.

Many different ways to do this.

I think that having high current 24/7, good turnover, but without breaking the surface, allows good O2 all the time, and while you lose a little more CO2, during that 8-10 hour dosing period, it's not that much.

So it really is more about the sticky micro bubbles, using less energy vs a powerhead(not really).

Otherwise just have more current.

I'll be upgrading my tanks in the coming year, going all beveled edge, ADA style, T5's, and Ecotech wavetimer systems. Likely will use wet/drys and moderate flow through them, but high current via the Ecotechs.

Regards,
Tom Barr

 

[evandro.carrenho]

To be accurate, I use a co2 diffuser with an air pump. My air pump is a Hagen Elite 801, it is enough to put air through the co2 diffuser, not sure if the diaphragm will need replacement too shortly, as it has been a couple of months that I run it... but it hasn't shown any signs of damage yet.

I have two distinct diffusers, but I think it would work fine if you use the same with check valves properly placed.