DIY CO2 queries

**elwaynetan** · 29th Aug 2012, 13:43

Hello...

I am setting up my DIY CO2 system tonight. I want to ask, does the length of the air hose between the mixture bottle and bubble counter affect anything with the pressure of CO2? Also, the length between the bubble counter and check valve, and the length between the check valve and diffuser...

I've also read from a blog that from his experience, he uses an air stone under the filter inlet instead of a diffuser because the CO2 from the bottle may not have enough pressure to push through the diffuser unlike from the canister filled with CO2.

Any advices?

Thanks.

**James_Bond** · 29th Aug 2012, 21:26

It depends how many bottles and the capacity of the bottle you are gonna use. For sufficient pressure, a 1.5L bottle for carbonated drinks will produce enough gas pressure to atomize the co2 gas. Also that depends on the amount of yeast to sugar ratio and you cannot be too stingy in that case. The air hose shouldn't have too much slack anywhere along the setup or else you won't be able to get enough air pressure. Check valve should not be too close to the diffuser but can be closer to the bubble counter.. I did a Diy setup recently and was able to get it to work.. not expert advise though!

**elwaynetan** · 31st Aug 2012, 00:53

Originally Posted by James_Bond

It depends how many bottles and the capacity of the bottle you are gonna use. For sufficient pressure, a 1.5L bottle for carbonated drinks will produce enough gas pressure to atomize the co2 gas. Also that depends on the amount of yeast to sugar ratio and you cannot be too stingy in that case. The air hose shouldn't have too much slack anywhere along the setup or else you won't be able to get enough air pressure. Check valve should not be too close to the diffuser but can be closer to the bubble counter.. I did a Diy setup recently and was able to get it to work.. not expert advise though!

Well, since I am going to use 1.5L bottle with another one as back up... what is your ratio for your yeast and sugar? the amount of water in your bottle? Maybe I can use your formula as a guide for myself! Thanks!

**dc88** · 31st Aug 2012, 08:01

For a 1.5L bottle you can use any where between 1 - 2 cup of sugar is fine.

Basically the more sugar it last longer until a maximum point (because too much ethanol built-up will stop the fermentation anyway) so any excess sugar won't buy you more duration.

On the other hand the more yeast the more CO2 produce (faster startup, a lot of bubble in the begining) but shorter duration (running out of steam sooner). I found a good balance point is 1/2 tea spoon (2.5ml) yeast to 2 cups of sugar.

And one more important item : Baking Soda (Sodium Bicarbaonate) the usual plain one sold at NTUC (look for baking ingredient) will do. Use 1/2 teaspoon for a 1.5L bottle.
Baking soda stabilize the water in the bottle when CO2 produces (CO2 make the water acidic, with Baking Soda it neutralize the PH) Also some says that the sodium in baking soda is toxic to the yeast so it control the yeast growth rate to be more constant.

This recipe normally last 2 weeks for my case, producing 1 bps feeding to a reactor.
Air-stone will work well too. My favorite setup is to use the DIY Venturi Reactor with a powerhead (Tom Barr's invention). Which allow the use of timer to control it to syn with the lighting period (with lots of fine CO2 mist) while venting away the CO2 at night.

btw one thing I learnt is that if scale this recipe to a larger bottle, you scale the sugar and baking soda amount but the yeast should keep the same (i.e. 1/2 tsp yeast produce 1 bps).
I am running a 2.5 L soda bottle now which last 3~4 weeks

**elwaynetan** · 31st Aug 2012, 15:39

Originally Posted by dc88

For a 1.5L bottle you can use any where between 1 - 2 cup of sugar is fine.

Basically the more sugar it last longer until a maximum point (because too much ethanol built-up will stop the fermentation anyway) so any excess sugar won't buy you more duration.

On the other hand the more yeast the more CO2 produce (faster startup, a lot of bubble in the begining) but shorter duration (running out of steam sooner). I found a good balance point is 1/2 tea spoon (2.5ml) yeast to 2 cups of sugar.

And one more important item : Baking Soda (Sodium Bicarbaonate) the usual plain one sold at NTUC (look for baking ingredient) will do. Use 1/2 teaspoon for a 1.5L bottle.
Baking soda stabilize the water in the bottle when CO2 produces (CO2 make the water acidic, with Baking Soda it neutralize the PH) Also some says that the sodium in baking soda is toxic to the yeast so it control the yeast growth rate to be more constant.

This recipe normally last 2 weeks for my case, producing 1 bps feeding to a reactor.
Air-stone will work well too. My favorite setup is to use the DIY Venturi Reactor with a powerhead (Tom Barr's invention). Which allow the use of timer to control it to syn with the lighting period (with lots of fine CO2 mist) while venting away the CO2 at night.

btw one thing I learnt is that if scale this recipe to a larger bottle, you scale the sugar and baking soda amount but the yeast should keep the same (i.e. 1/2 tsp yeast produce 1 bps).
I am running a 2.5 L soda bottle now which last 3~4 weeks

how big is your 1 cup of sugar? haha!

**dc88** · 31st Aug 2012, 22:29

Standard cup 8 oz. just use those disposable plastic cup to measure.

**VSGenesis** · 31st Aug 2012, 22:44

1.5L
4cups sugar (measuring cup - stole from my mom baking cupboard)
1/4 tsp yeast
1/2 tsp baking soda

The more yeast, more bubbles; runs out faster

Don't use atomizer as it requires a higher pressure. It work when I use it but my bottle became bloated like nobody business. Use the normal $6-$8 glass diffusor good enough.
Personally, good for 3 weeks or so. I use it when CO2 Tank empty and being the lazy type, I wait till weekend before I head down to Bioplast to refill CO2 tank.

You should check out Shadow's blog (he did dual bottle)

**elwaynetan** · 2nd Sep 2012, 01:38

OK! After passing a hurdle, now my CO2 is working... 1 bps. Finally...

My set up;

1.5L bottle -> bubble counter -> check valve -> glass diffuser.

Mixture: 10 satchets of sugar (sold from NTUC) + 1/2 teaspoon of yeast. Dissolved sugar in warm water before adding yeast on the surface.

Anyway, 1bps is good for a tank of glossos, tenellus, hair grass, java and thailand moss? my tank is less than 2 ft.. haha.

Let's see how long this set up will last~ haha!

**elwaynetan** · 2nd Sep 2012, 01:39

Originally Posted by dc88

Standard cup 8 oz. just use those disposable plastic cup to measure.

standard disposable cup sounds a lot! haha.. 2 whole cups of it!

**dc88** · 2nd Sep 2012, 13:42

Originally Posted by elwaynetan

OK! After passing a hurdle, now my CO2 is working... 1 bps. Finally...

My set up;

1.5L bottle -> bubble counter -> check valve -> glass diffuser.

Mixture: 10 satchets of sugar (sold from NTUC) + 1/2 teaspoon of yeast. Dissolved sugar in warm water before adding yeast on the surface.

Anyway, 1bps is good for a tank of glossos, tenellus, hair grass, java and thailand moss? my tank is less than 2 ft.. haha.

Let's see how long this set up will last~ haha!

Minimize the water surface agitation during the day should be fine for a 2ft tank with 1 bps. What filter do you use ?

**elwaynetan** · 2nd Sep 2012, 16:43

Originally Posted by dc88

Minimize the water surface agitation during the day should be fine for a 2ft tank with 1 bps. What filter do you use ?

How would water surface agitation affect 1bps? I am using Eheim 2222 with half pressure.

**dc88** · 2nd Sep 2012, 22:50

Too much water surface movement makes CO2 escaping from water to atmosphere quicker.

**elwaynetan** · 3rd Sep 2012, 15:45

Ok... So now my CO2 is running fine. How do I know if my CO2 in the tank is not potent enough to kill my livestock? Am planning to put in 10 Fire Reds tonight into my empty tank to test water...

**elwaynetan** · 3rd Sep 2012, 15:46

Also, how long does it take for plants to start pearling? haha!

**felix_fx2** · 3rd Sep 2012, 18:18

Originally Posted by elwaynetan

Also, how long does it take for plants to start pearling? haha!

The easy way of putting it.
When the plants make o2 faster then the surrounding water can absorb.

Highly depends on your lighting vs the below harder to count section.

(this part even I skip, but just good FYI)
It is also affect by how saturated the water is by gases.
Also temperature affects the rate which gases are absorbed

**dc88** · 3rd Sep 2012, 22:42

Check your KH make sure is not less than 4.
Too low a KH when inject high level of CO2 might cause a PH crash (suddenly go very low) can kill the fish.
But normally DIY CO2 will not reach this level.
A healthy balanced system the PH is around 6.5-6.8 with the KH around 4.
But if you dose PO4 (plant nutrient) the PH may be 6-6.5 range still be ok.
Just make sure KH not too low. If need to adjust KH, just
add baking soda 1/2 tsp to 100L give about 1 degree KH.
If you keep shrimp make water KH adjustment slowly don't stress the fellow.