why 2 nutrafin co2 systems on a 40g

[tetrin]

this has been bugging me for quite some time. why does nutrafin recommend 2 of their units on a 40g or more?
if i try to compare a 2l soda bottle with one nutrafin system, the bubble generation rates don't seem to much different (though i'm not exactly sure), since it depends on the relative concentrations of the sugar and yeast. so if the diffusion method is the same, they are supposed to give similar amounts of dissolved co2.
am i completely off the track somewhere?
any comments would be welcome...

 

[czcz]

I think the small size of the Hagen canister allows the alcohol to kill the yeast faster than in a larger container, therefore if you keep ratio and effective time of mix constant, youll have less CO2, because there's less fermentation happening. I may be wrong. 2 CO2 canisters certainly produce more CO2 than one canister, with the mixes constant.

As an aside, I got over 100% increase in dissolved CO2 from one powered diffuser than two passive ones (Hagen and bell). I wouldn't be surprised if you beat two Hagen systems with one 2L and a powered diffuser.

Remember venturii injection for CO2 experiment? I'm doing that now at my sump with flimsy 2Ls. Only tested for a few days, but it appears that as long as the mix is producing gas, water won't enter the line and flood the bottles. If I squeeze a bottle, then release, water enters part of the line, but is pushed back to the sump piping as more CO2 is produced. Its very effective, matching my powered diffuser numbers. Perhaps your experiment (where water entered DIY canister after a day iirc) was because of too much yeast, which puttered out? Just a thought.

HTH

 

[tetrin]

thanks czcz.
well, if the yeast-sugar ratio is kept constant, the amount of alcohol produced in the hagen system would be small too, compared to a 2L soda bottle. i mean, the reaction has to be the same. but 2 systems would definitely produce more co2, but so would 2 2L bottles...

glad to hear that the venturi injection is working. i'm going to try it again. although i'll still include a check valve in the line