Diy Co2 In Small Tanks

[MtPansy]

Hey all,

I have 2 planted tanks, a 3 gallon and a 10 gallon, and would like to put a homemade CO2 system in each (those systems made from bottles, yeast and sugar.) My reasons for this are two-fold; first, I want my plants to prosper, and secondly the pH in my area is around 7.8, which is too high for the tetras in my 3 gallon. There are all sorts of resources on how to construct your own injectors, but very little on what to expect once it is up and running. How drastic will the pH drop be? How much yeast should I use on just a little 3 gallon? My kH is very high, so I don't expect much of a crash in my ten gallon, but I still don't want to endanger the residents needlessly.

Any help very much appreciated.

 

[RadaR]

For starters, ph of 7.8 is fine for Tetras. In fact I've seen plenty of tetras thriving in a pH that high. A lot of tetras arent wild caught anymore and therefore have become used to higher pHs.

DIY CO2 is fine to use on those size tanks. I personally wouldnt use DIY CO2, instead I'd use liquid carbon (Easycarbo). Sooooo much less work.
Liquid carbon doesnt effect pH btw.
When we inject CO2, we usually see a drop of about 1. The fish arent badly effected by this at all. Here is a guide on setting up a DIY system. It's using the hagen kit but you can simply adopt it to be used with 2x2litre coke bottles.

Do you actually need any carbon addition? (this is largely based on how much light is over the tank). More light = more CO2. More CO2 = more nutrients.

 

[stevereade]

My LFS has a section for soft and hard water which includes Tetra, why not take them in and they'll prob exchange them for hard water Tetra.

Oh and what plants are in your tank, What lighting do you have?

 

[lljdma06]

For starters, ph of 7.8 is fine for Tetras. In fact I've seen plenty of tetras thriving in a pH that high. A lot of tetras arent wild caught anymore and therefore have become used to higher pHs.

DIY CO2 is fine to use on those size tanks. I personally wouldnt use DIY CO2, instead I'd use liquid carbon (Easycarbo). Sooooo much less work.
Liquid carbon doesnt effect pH btw.
When we inject CO2, we usually see a drop of about 1. The fish arent badly effected by this at all. Here is a guide on setting up a DIY system. It's using the hagen kit but you can simply adopt it to be used with 2x2litre coke bottles.

Do you actually need any carbon addition? (this is largely based on how much light is over the tank). More light = more CO2. More CO2 = more nutrients.

The one big drawback, IMO, to easycarbo is that you cannot really measure the Carbon in the tank. Because DIY involves actually injecting the gas, you can measure CO2 gas levels (different from easycarbo, which is not the gas) levels with a dropchecker and you'll know where you stand. For me, it is enough of a drawback not knowing, that I'd prefer to deal with the yeast and mixing. I like to be able to adjust my levels if something changes in my dropchecker. I also cannot abide the smell of easycarbo and other Carbon products. Smells worse to me than the yeast. In smaller tanks, the DIY pressure will be sufficient for you to use the nano-sized glass diffusors and get even better results with regard to distribution. It's up to you really. Ease vs. being able to measure. Both grow nice tanks.

 

[MtPansy]

My 10 gallons has 30 watts (3 watts per gallon), and my 3 gallon has six (2 watts per gallon), and of course neither tank is particularly deep.

Ten gallon stock:
pygmy chain swords
dwarf anubias
and something that looks like it could be Needle Leaf Ludwigia (will try and take a picture later)

Three gallon stock:
Oval ludwigia
water wisteria

I've been fertilizing occasionally with Leaf Zone.

Would the injector for the three gallon still need to be a 3 bubbles/minute? Should I use less yeast in the reactor?

 

[stevereade]

You don't need CO2 with those plants at all really, I'd dose some ferts first and see how that goes, they're pretty undemanding plants.

But then again 3WPG, you may need something to make up for the fact that you have very high light. But like I say I'd try ferts first or nothing if all your plants are doing fine.

 

[RadaR]

It's worth mentioning that the "WPG rule" doesnt apply on smaller tanks.
Anyway..
The 10gallon has a lot of light. You'll need some carbon addition for good plant growth and to avoid algae.
The 3gallon really doesnt need any carbon addition. I'd leave it as it is.

 

[MtPansy]

Thanks for the advice! I did some more research and went with a pressurized canister instead in the 10 gallon. I was getting some hair algae over night (or spyrogyra or something, growing like crazy with the texture of fine human hair), hope that the CO2 will help there. I'm leaving the 3 gallon as it is, because I'm getting some good growth and no discernible algae.

I have another question, if you'll indulge me. The plants in the 10 gal tank are the only thing that is new, otherwise the tank has been established for over a year and no new residents for about 3 months. I noticed some of my cherry shrimp were in distress, and I thought it might be the drop in pH from the CO2 (no idea how quickly it drops) so I tested my water. Levels all good except for just a hint of ammonia! Is my biological filter compromised, or can the addition of plants cause a spike?

I did a 40% water change and dosed heavily with Prime. If I continue to use Prime to control my ammonia, with it hinder the re-establishment of the bacteria?

Thank you again, your advice has been invaluable.

 

[RadaR]

Adding plants will certainly not give rise to amonia unless they are decaying. Some ferts that contain N+P (tropica plant nutrition+) can sometimes give a false ammonia reading. Could it be that?

In combination with water changes and good plant growing, you shouldnt see this rise in ammonia again.