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Passive CO2 experiment update


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I have completed testing passive co2 in several tanks and the results clearly show a BIG difference in plant growth. 

there are 2 takeaways that you need to know to be successful.

1. you have to refill daily. i do it in the morning and by the time lights go out most of the gas is gone. the next morning you have to refill.

2. after a few days or weeks, you will see the chamber stays more and more full of gas requiring less top up. this is because other gases diffuse into the chamber and replace the space for the co2. you can tell its not full of co2 because if you put some airline hose in and suck out the air, it will have no taste. if you do that after you fill it with co2 it fills your mouth with that "soda gas" taste and you know its all co2. i was inspired by the felllow in SF and noticed that he only filled a few times a week but his bottles were still half full. i think that is residue gas from the tank that naturally gases out over a few days. when you fill a bottle with pure co2 you will be amazed how fast the plants pull out the gas and the container empties.

and C.  i cut the narrow cap section out to allow greater dissolution rate into the tank. that seemed to also really amp up the gas exchange.


all in all, very much worth the minimal cost of soda stream conversion etc and since i work on tanks every day anyway, the labour is irrelevant. i suggest you give it a try.




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Is the Passive CO2 the only change you made in that tank?

I also decided to try a cruder version Justin's passive CO2 set up. I'm thinking  my occasional passive CO2 experiments might have in part, triggered the sudden growth spurt in my PSO.  It has nearly taken over the 10 gallon project tank. The PSO was never the fast growing weed it was supposed to be. It has now grown above the waterline and may be self propagating. 

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