C02 & Air Pumps

[TankWatcher]

Hi discus & planted tank enthusiasts,

Just wondering if any of you with planted discus tanks use pressurised C02 & run an air pump at the same time.

[erikc]

No, never run C02 with an air pump. The bubbles breaking the surface will reduce the amount of C02 dissolved in your water. You will have to count on the plants for the oxygen, the tricky part of CO2 is trying not to lose it :)

[Chad Hughes]

I have to agree. Air pumps with CO2 is really not necessary. In fact, you'll end up going through a lot of CO2 due to it's release from the tank.

If you have enough plants that you require CO2, then you are producing adequate oxygen and there shold be no need for air pumps. I run a pressurized system 24/7 on a controller. I do not own an air pump and have ahd excellent results!

Best wishes.

[TankWatcher]

Yes, this was the expected answer. I just wondered if planted tank enthusiasts, who liked their discus more than their plants, sometimes compromised C02 for the discus . It was just that today my bubble rate increased enough while I was out, that my discus were a bit oxygen starved. A water change & an air pump for a couple of hours fixed them up, but I'm a little concerned for them. Usually when my bubble rate wanders, it wanders down wards. This was new that it wondered up wards instead. I guess I will need to check the rate more often than usual for the next little while.

At least I think it was the bubble rate that caused it. My pH controller has been getting some white fluffy stuff on it lately. I clean it at wc, but it keeps coming back. Wondering if that might be throwing the pH readings out & so the system pumped in more than it should have?

[Chad Hughes]

Hmm.... that is interesting. So your controller is not controlling? Am I reading that correctly? No matter what your bubble count is, your controller should never allow your Ph to exceed it's settings. Is the white matter fuzzy or hard (like calcium build up). Where is your Ph probe? Put it as far in to the bottom of the tank as possible if it's not there already.

[scolley]

No, never run C02 with an air pump. The bubbles breaking the surface will reduce the amount of C02 dissolved in your water. You will have to count on the plants for the oxygen, the tricky part of CO2 is trying not to lose it :)This is standard thinking, but it is not entirely correct.

To say "never" with regard to running air into your tank while using CO2 is misleading. Using lots of air in a small tank, with a modest means of CO2 injection, you might be able to lose CO2 faster than you can replace it. The end result being CO2 concentrations hovering at atmospheric levels (4 ppm, or what ever that is). In that case it's a problem.

But at the other extreme - my own tank as an example - in a big tank (180g) with an aggressive means of injecting CO2 (venturi), I have an airstone running constantly in the corner and I have no trouble keeping my CO2 at 25-30 ppm. And it's not like I'm chewing up CO2 like crazy either. I replace my large (20 lb) tank every 6 months or so.

So "never" is the wrong word. Maybe it's better to say to be "careful", because it does outgass CO2, but whether or not it is too much outgassing depends on many variables.

Also, "count"ing on your plants for O2 is typical planted tank thinking. But I think it is more applicable to the light fish loads found in typical planted tanks. Generally speaking planted discus tanks far exceed the fish loads of your average planted tank. For that reason it's reasonable to expect that what works when you have a tank of tetras may not work for a tank of discus. That O2 just may not be enough.

For that reason I do not count on the plants for oxygen, and use an airstone.

But since I do not measure oxygen in my tanks, I cannot speak with authority on this point. Though I can say that my fish seem to breed more when I'm running an airstone. So I take that as an indicator of "happiness", and that my moderately planted tank was not generating quite enough O2 for my big ole' discus without a little help.

[Chad Hughes]

Steve,

Excellent points!

I, myself, have never used an air stone in my CO2 injected tanks. I have a 150 that has a 5lb CO2 tank that gets refilled once a year. I also have another 110 that has a fluval 405 on it. When the water line gets low and surface agitation increases from the exposed return, the CO2 in that tank is on more frequently. I am guessing that it's due to the rise in Ph from the loss of CO2. When I was first studying about plants and the use of CO2, it was tought that surface agitation will cause a loss of CO2, and I believe that is true due to my observations. On the other hand, running a small air stone in the corner of a huge 150 - 180 gallon tank is not like disturbing the surface enough to cause any noticeable CO2 loss. My plants pearl constantly, so IMO this is the "natural" air stone effect and it's likely pure oxygen.

That's interesting that you mentioned that your breeding increases with air. I'm going to have to give it a try now and see. I am cycling some sponge filters in the sump of one of my tanks. I'll have to run a line up to the tank with a stone to see if they increase from weekly to who knows how often! LOL!

Thanks again for the great info share!

Best wishes!

[scolley]

I, myself, have never used an air stone in my CO2 injected tanks. I have a 150 that has a 5lb CO2 tank that gets refilled once a year.
That's pretty impressive Chad. I don't know how you do that.


My plants pearl constantly, so IMO this is the "natural" air stone effect and it's likely pure oxygen.Pearling is the visible evidence of oxygen saturation in your water. Assuming you have good circulation, that is proof that your water has as much O2 in it as it can possibly hold. Problem is, your plants don't pearl constantly.

At night, after a day of cranking out O2, your plants not only release CO2 into the water, they also absorb O2. So while they were making it with the lights on, they are draining the water of it while the lights are out. I.E. - they don't pearl at night, just the opposite in fact. For that reason - even if I don't run an airstone during the day - I always run one at night.

Again we run into the problem of the size of your fish. With a tank of tetras you are much less likely to run into oxygen deprevation in planted tanks at night. Though with discus it is much more likely. If you doubt this... go peruse planted tank forums, and you'll see many, many people talking about their fish gasping at the surface when they get up in the morning. The reason is simple - plants use some of that O2 at night.

So, at the risk of being repetitive - airstones can make a lot of sense in a planted discus tank. :) At the very least, at night time.

[Wahter]

You can run an airstone with an air pump overnight - that way there will be more O2 gas exchange since the plants respire during the night.


Walter

[Chad Hughes]

Steve,

You have really summed it up well. I did know about 90 percent of what you stated. I was not aware that plants use O2 at night. Interesting.

Well, after our last post I went out and bought an air pump, some air line and some air stones. I'll be doing a major cleaning of my show tank tomorrow and guess what I'll be adding to the tank?? AIR! LOL!

Thanks for all the great info. I'll keep tabs on the CO2 usage to see if it escalates or not. Right now my tank is super still and a 5lb CO2 tank lasts about a year.

Although I have never seen any of my fish at the surface of the water in the AM, I am sure that the air stones will be of more benefit than not. I have 16 discus in a 150 gallon tank and I am sure that they are using a good bit of O2.

Thanks again for all the great info! I have had planted tanks for years and havebeen dead against air stones and agitation of the water. You turned me out! LOL!

[scolley]

Chad - that's kind of you. Though my intent was not to prove that airstones are needed in a planted discus tank.

I just wanted to point out that it ain't necessarily the end of the world for your CO2, and that it might actually be beneficial for your discus. ;)

[cyberhog05]

In my case I have to run an air stone on my 110t, I may not have enough plants yet to supply enough O2. I will go through tons of Co2 before I suffocate my fish. It cost me 18bucks to fill my 5lb bottle with food grade Co2. Thats nothing compared to the cost of replacing my Discus. I left the air off one night and I had some very unhappy fish the next morning. And one panicked owner:(. I am gonna try to use air at night only and see how it goes.

[TankWatcher]

Thanks for all your help. I will get a timer & at least run an air stone at night, in one corner of my 138G.

I prefer to lose a little C02, than my discus (although I don't think I was actually about to lose one anyway, but I could tell they were 02 starved on that occasion).

[Chad Hughes]

Just a quick question...

How are you all monitoring your CO2? Is it just bubbling in to the aquarium without any control or are you runing it with a Ph controller?

[scolley]

I've got a controller. Plus a drop checker, because that controller is only as good as the accuracy of the probe - which drifts and has to be recalibrated periodically. That is until it wears out (as indicated by slow response to change and/or trouble recalibrating), about every year, when in needs to be replaced.

The drop checker provides a little extra comfort. And when I doubt that, I pull out a "dip" tester. But day-2-day, the pH is set with an AquaController III.

[cyberhog05]

I am on the same boat as scolley! Under my tank looks like a wiring nightmare.

[tacks]

Hi guys I have a 150 tall. I have a PH controller and a drop checker. I run an air stone on the lowest setting 24/7. I go through a 10 lb every 6 mons.not a lot of money for piece of mind. HTH Ed

[TankWatcher]

Mine is pH controlled, but you have reminded me that I am overdue for calibration. I use to use a drop checker, but for some reason stopped. Might dig it up & put it back into use.

About last Sept I had to replace the original probe. The new one gets this soft fluffy white stuff that grows on it. I do clean it off with each wc, but I wonder if this effects the accuracy of the probe reading? Anyone else have this white fluffy growth. It doesn't grow on anything else other than the probe?
Thanks again guys :)

[TankWatcher]

I think there is something wrong with my regulator. Tonight I walked past the tank & the C02 was bubbling at such a rate that from the opposite end of the room you could see huge bubbles & hear the noise :mad:

For the time being, this might mean the end of my C02, as I can't continue to use it if it is going to do that. I have a spare regulator (bought 2nd hand), but if it doesn't work, a new regulator isn't on my my shopping list for now :(