[superpedro]

Hi!
This is a system that enables you to use CO2 application without a big cost.

The system I'm building now is to replace the bottled CO2 I'm currently using in my small cab.(link in my signature), with CO2 brewed from sugar, yeast, and water.

The dosage system is made of an submersed container, that enables water to exit the container at the bottom. The hose from the “brewery” is connected with a T-piece to the CO2 container under water, and the other end to the electronic valve.
You need to calculate the size of your cab., and the CO2 amount needed to raise the level to 1500ppm (1,14L of CO2 for each m3). Then you build the submersed container in the exact size for the amount needed.
The sugar to water ratio is 100g pr. L, and no more than a fingernail of yeast is needed to start the production. This mix delivers about 20L of CO2 over a ten day period.
A good idea is to have two half size cans for the brewery, and replace one each 5 days for the most steady flow.
You set up the brewery size, so that the container gets filled within the amount of time, you have between your air replacements, and you should oversize it. Excess CO2 will leave the system through the bottom of your container and wont make you overshoot your target level. You can keep the container outside the cab., or fit a lid with a exhaust hose.
Start the mix a day before connecting them to the system, it takes some hours to get going.
The e-valve is controlled by a digital timer with one minute intervals, and the ventilation of the cabs on another one, set to exchange the air prior to release.


Here you see the principle in action.(old video from my first try of concept)




The system was scaled for a 25m3 room with a 600W hps running in a closet that exchanged air from the room. It used 100L yeast mix for 5 replacements of the room during each 12 hour light cycle.

The old big cab.


Later in that same system, I tried using 2 floating switches in the CO2 chamber, to control the start of the fans when the system was almost full, and the second switch was fitted with a delayed off mode, that kept the e-valve open for 2 minutes for the CO2 to escape. That way I got to use all my CO2.


The system I'm building now that holds 1,3L of CO2 for my small cab.:

Materials:


I use an air hose connector from an aquarium store to fit the CO2 line from the container:


The finished product, there is a small gap between the CO2 container and the bottom of the aquarium. (I'll ad a few pics when it is up and running)


Since my new cab is a micro(less air for each plant = you either need frequent exchanges, or a constant addition), I've added an extra feature, with at needle valve bypassing the e-valve, to make a constant flow equal to the consumption of the plants. I'm going to adjust the flow by making a measurement of the CO2 level prior to the exchange cycle(hand held devices for indoor climate measurements can be leased for a few days where I live) and then adjust the valve to add just a bit more than the used amount in between the cycle.
I need an extra e-valve for night shut-off.


BTW, the reason I want the water column above the CO2 container to be so many times taller than the container itself, is to have an almost steady pressure for the release.

Hope you like it!

That was pretty interesting and a lot of thought and work went into it,I have one question though that I've found in my experience means everything.Do you have your source on a co2 controller?I hear you keep saying cap is that a cap PPM-3 you're talking about?I've used co2 for a very long time some of it pretty much wasted because of co2 fluctuations.I hear so many people trying things that I know from experience just wont achieve results but they have to go through what I went through I reckon.A cap PPM-3 is the cheapest controller out there but its done the job for me now for over two years.Before that it was a worthless device called a cyclestat.What a difference controlled co2 makes

[superpedro]

Originally Posted by sparkjumper

That was pretty interesting and a lot of thought and work went into it,I have one question though that I've found in my experience means everything.Do you have your source on a co2 controller?I hear you keep saying cap is that a cap PPM-3 you're talking about?I've used co2 for a very long time some of it pretty much wasted because of co2 fluctuations.I hear so many people trying things that I know from experience just wont achieve results but they have to go through what I went through I reckon.A cap PPM-3 is the cheapest controller out there but its done the job for me now for over two years.Before that it was a worthless device called a cyclestat.What a difference controlled co2 makes

LoL, no that was an error. I meant my cab English isn't my first language, if something else needs clearing up, please let me know.

It is not controlled by an expensive dosage device.
I simply calculate the amount needed to raise from 360ppm to 1500ppm, and inject that amount after the air in the cab has been exchanged with outside air.
The amount injected in between the air exchange cycle (2 hours in my cap), is adjusted with the small needle valve, and set by a single measurement at a time when the cab is full of fast growing plants.
The air exchange and co2 injection is done in 2 minutes in my small cab, and whit that, the ppm level is reset to 1500ppm every 2 hours.
My goal is to stay within +/-100ppm.

It could be used as an bio alternative for bottled gas with a CAP device.

[foomar]

Interesting post and well thought out superpedro.

Have been brewing beer on and off for decades useing the heat from the veg box to warm the buckets and rougthly collecting the gasses evolved and feeding them back into the veg box below.
Currently have a dozen demijohns of wine bubbling away with tubes from the airlocks feeding to the middle of the plants , no fan just natural convection and the plants grow a little bit better than without it.

Reading your post has encouraged me to look into makeing my setup more efficient and make better use of a controllable flowrate , worth a shot if you do homebrewing anyway and a good excuse to start if you dont.

My solution will probably involve bin bags , a box full of aquarium bits and an ancient cyclestat timer for version one with an air pump running in the bag to inject direct to the plants when lights are on.

One thing i have noticed is that a much higher number of plants will show sex earlier than expected in mid to late veg and or within a day or two of going into flower , i suspect ethylene gas or some other byproduct of the yeasts life/death cycle may be responsible but am not complaining and see no more hermies than usual.

[billy_big_bud!]

i dont understand it but that doesnt mean im not impressed.

[superpedro]

Thanks guys
@foomar: That sounds good, I'd like to know how it works out for you.

Here is a picture of the simple injection system setup. 1,3L of CO2 releases in 8 seconds:


When running a microcab like mine, I would recommend to add the slow release in between the exchange, or a rapid exchange cycle.
In a large setup with plenty of air for each plant, the CO2 level won't drop as fast, and you should be able to stay within the desired range when using the right air exchange frequency.

BTW, adding salt to the water in the aquarium makes it a better barrier, otherwise a tiny amount does diffuse through the water. And I won't recommend using plastic tubs with soft sides for the build. Thats why I have a wooden frame around the first one.

The first full run of the system will be included in my grow thread.

Cheers!

[pontiac]

cool concept but kinda extreme :p

[ArcticBlast]

very cool, i love your DIYness lol

ArcticBlast

[Arthritis_sucks]

Quick question on the Co2......I have a sealed room where the light is on a closed ventilation. just picked up a tank, regulator, an a 15 min. interval timer. Can I run it with out ventilation to exhaust the dead Co2 every other 15 mins. Reason I am asking is I am buying a fan in a week but want to utilize the Co2 if I can. Any help would be greatly appreciated.