Aeration in planted tank

[Dave Cushing]

Is it a good idea to use a bubbler in a planted tank? So far I will not be having a CO2 system, but that may change in the future though.

I posted in the Newbie section all the specs for the tank I am setting up, but for those who only read here:

50 gal
Central/South American plants
Soft Water
Neutral to slighty acidic pH

More details can be seen here http://www.aquariacentral.com/forums/showthread.php?s=&threadid=14251

I am getting all this setup so I am looking for any reccomendations I can get. Already, I have increased the lighting in my tank thanks to the advice of the posters here.

Thanks

Dave

[Dtman]

No I wouldnt add an airstone or bubbler into a planted tank. You want as little surface agitation as possible, as it will gas-out whatever Co2 you have in there. If your plants are doing well, they will provide oxygen to the water for your fish.

[djlen]

In a non-injected tank CO2 will be added to the tank through gas exchange by aerating the tank and good water movement. Keep in mind that the CO2 concentrations in a non-injected tank are quite low 'Gassing off' occurs in CO2 saturated water. Aerating it will actually draw gas into the tank from the atmosphere(minimal though it may be).
I'm sure someone will correct me on this, but I believe we're talking about somewhere between 2 - 4ppm CO2 in the atmosphere.
Len

[djlen]

A question for you Dave. I noticed you are using Flora Base by Red Sea in combination with Flourite, as a substrate.
Can you tell us about it? How do you like it? How does it affect CO2 concentrations in the water table(if at all)?
Len

[Sumpin'fishy]

Good questions, Len. I have asked about Flora Base in a different post!

[Dave Cushing]

Good questions, but no answers yet. I haven't set up the aquarium yet, I have been getting some good comments on my other port in the Newbie forum which has caused me to change a couple of things, like adding more light. My LFS owner swears by it though. It is all he uses and sells.

This now has caused a debate on whether I should use a CO2 injection system. I will pose this to the plant experts:

50 gal tank (36L x 15W x 21H)
2 x 96w PC Lights

Substrate 24 lbs Red Sea Flora Base
7 lbs Flourite

I am going to keep soft water fish (Angels, Swordfish, and Tetra's)

Plants are all Souh/Central American (Vals, Swords, Anacharis, Cabomba)

Will I need to increase the amount of CO2 in solution?

Red Sea advertises that no further injection is needed, but I am leary of believing advertising.

If everyone thinks CO2 is needed, is a DIY setup reliable, or should I set up a pressurized tank system? Since I am still in the setup phase, I would prefer to do things right the first time.


Dave

[djlen]

I don't know whether buffering(for lack of a better word) water down is a good mix with CO2 injection or not. I tend to think not.
The claim that, "no further injection is needed"......what does that mean? Needed to lower pH?
As a fellow aquarist said on another forum, "we do not add CO2 merely to lower pH, but to add carbon to the water table".
And I don't know what the substrate does to buffer the water.
In any event, with all that light, unless you are holding 22 - 28ppm CO2 you may be looking at some algae issues in the not too distant future.
IMO, in a 50 gal. tank a DIY system is not going to do it for you. I would never go back to using DIY in any tank above 30 - 35 gals. It wore me out, and was too inconsistent and unreliable.
Just my opinion. Others, I'm sure will differ.
What is you pH/kH ratio?
Len

[Dave Cushing]

Don't have any water in the tank yet to get a ratio. I am still planning and building the infrastructure. What ratio do you recommend shooting for?


I am convinced that a CO2 system is necessary. I was doing some internet reading and it seems to be the concensus. I agree that a DIY source is high maintenance. I was thinking though of building my own reactor, and using a gas bottle as the source. I was reading another post about a DIY reactor made from PVC. I know PVC has a tendency to leak chemicals over time. Does anybody have experience with this?


Dave

[plantbrain]

At your light intensity, there is no way this will add enough carbon to prevent the plants from going after the CO2 in the water. This will drive the pH up. CO2 is an acid and the plants will remove it most all it enough to effect the pH.

Now if you had say, 60-90w on the tank, then it might work okay/well etc.

Anyway, adding CO2 will help no matter what. Expecting the substrate and fish to do everything is not realistic unless you have slower growth and non CO2 methods/low light etc.

Whether you want to use CO2 is up to your goal with plants. They will grow better with CO2. Even at lower levels, but it's not "required" at low levels.

Slower plant growth is better achievced by lowering light, not trying to add CO2 to the substrate.

CO2 gas tanks are easy and require little maintenance once set up.
You prune the plants more but selling off the cuttings can make it very worth while.
A gas tank, reg, needle valve will run about 125$.
Cost 8-15$ to fill(about 2-3 years with your tank) and you can branch off this system for another 15$ for another valve for each new plant tank with CO2 you might want later.

Regards,
Tom Barr

[Dave Cushing]

Tom,

Either my brain is scrambled because I'm tired or you left some words out.

Are you saying that at the lighting levels I have, that the substrate (Flora Base) will not add enough carbon and that the plants would start removing it from the water? This would cause the carbonic acid in the water to disassociate back to CO2 and water, thereby raising the pH.

This kind of answers other questions I had. It probably means that the CO2 settings are different for each tank setup, and a rule of thumb based on concentration is probably the best.

I have seen a concentration of between 20 - 25 ppm is optimal. Is this you r experience?

Thanks

Dave

[djlen]

I think basically what Tom's saying is that with the light intensity you're talking about, the plants will use all the CO2 available causing the pH to rise. At a lower light level injection might not be needed.

Yes, each tank has a different level of balance and therefore different requirements for CO2, nutrients etc.
The rule of thumb for 'high lighted' tanks is actually more like 25 - 30ppm CO2. Since you don't have your tank up and running you can take a sample of tap water. Let it gas off over night or at least a few hours. Then do a KH and a GH test on it to determine how hard(GH) your water is and also the degree of 'buffering'(KH) it has. Then, once you have the tank filled and running you test your pH and compare that value with KH to determine CO2/ppm. Generally, tap water(that is left to gas off) and tank water carry approx. 2 - 4ppm CO2.
Len

[plantbrain]

Yes, the first part is correct(not enough Carbon from the gravel at 4w/gal etc) and the range I tend to shoot for is about 20-30ppm CO2.

The pH will go up simply due to removal of the acid by the plants, the acid is the CO2 in the water. There are other potential processes that can raise the pH as well.

HCO3 is "the KH" at the pH's we used.

CO2:HCO3 ratio determines the pH _generally/ideally_ in most plant tanks.
CO2=>the acid and the HCO3 the buffer. A balance of the two gives the pH.
Remove the the acid, the pH goes up, remove the buffer/base the pH will go down.

Now I see no reason to add anything other than CO2 to lower the pH for the plants. If you use something other than CO2 to lower the pH, then the pH range has little meaning regarding plants. Plants want CO2 , not some "acid buffer" to grow. Plants need a lot of carbon to grow, if it's not CO2, don't bother. Excel can work also but only at lower lighting and the CO2 will work better IMO/IME.

You can depress the pH with other chemicals(other than (CO2/HCO3), but then the pH/KH/CO2 relationship is altered. It also complicates something folks are already having a tough time with and makes it VERY difficult to measure the CO2 and see if the plants are getting enough enough CO2.

This measurement is important espeically with high light system.
Even if you don't understand acid/base chem don't worry, this is the why, the how is easy. Use CO2 gas for this light intensity.

You can still use this product though................it's certainly would not hurt:)
But I'd use CO2 gas for sure in your case.

Regards,
Tom Barr

[Dave Cushing]

Tom,

I have already decided, based on your and other previous posts, that I will add the CO2 system.

Do you think that I am going overboard on the lighting? In a different post, i was recommend to get more light than I had (I have a ~70w set that I am going to return). This is why I ordered the 2 x 96 w which will give me ~4 wpg.

Thanks for all your advice. I actually understand acid/base theory rather well. I studied chemistry for quite a few years. I was just a little confused with the way you worded your post. But, I have it straight now.

I am sure as I get this tank set up (I hope to put water in it within the next two weeks) I will have even more questions.

Thanks again

Dave

[Rocketman]

I'm not a serious planter, but I've heard that 3 wpg is plenty. Of course, I'm not gonna try to upstage anyone else here, I'm just trying to get you a response sooner...however, if you have already ordered the other lights, you might as well go with them.