Yeast DIY CO2 with a solenoid valve.

[daskallu]

So I've started my first aquarium a year ago, and I've heavily planted it with Anubias, Java Ferns, Java Mosses, Proserpinaca Palustris, Riccia Fluitans and Red Root Floaters, so nothing too demanding.
It's a low tech 85l (52l of water) aquarium with an internal filter and heater set to 25*C (77*F). The stocking is 15 Ember Tetra, 12 Green Neon Tetras, 5 Otos, 2 Honey Gouramis and some Cheery and Amano shrimps.

I've been really interested in doing some CO2 lately and I've read about all of the common methods, from this community also. I know I probably don't need CO2 for this tank, but I've tried setting up a 2nd 30l tank with HC Cuba and Monte Carlo and those didn't really get a hold. Some of those plants are in this aquarium too and I want to save them.

I've read a lot about the yeast method and this one seems to be the most fun. This is the plan right now and I hope some of you can point out the flaws:
1. Currently I'm running a 200g sugar + 200ml water + gelatin solution; I think that lowering the sugar amount may also result in less CO2 per hour and I want to test this somehow
2. I'll be using 1.5l bottles with a narrower horizontal section area; I'm hoping this will reduce the surface of biological activity
3. I've setup a drop checker with 20mg/l solution and I'm also testing pH twice per day; at the start of the day and at the end of the day
4. Since I can't really regulate the amount of CO2 going into the aquarium, I think that raising and lowering the diffuser will impact how long the CO2 bubbles have to travel to the surface and therefor impact the dissolved CO2
5. I've ordered a solenoid valve and my plan is to setup a Y(T) junction on the airline tube. One way goes to the aquarium and another to the solenoid valve. During the day, I plan to shutoff the solenoid valve and open it during the night. My thinking is that, since there's less resistance on the solenoid valve path, the CO2 will just vent into the room and not reach the aquarium. A no return check valve is also needed on the aquarium path, so that the tank doesn't somehow drain through the other path lol.
6. I'm not using it right now, but I plan to setup a second bottle with water, to "wash" the gasses generated by the yeast solution, before going into the aquarium.

This is the plan so far. What do you guys think of it?

 

[ian_m]

5. I've ordered a solenoid valve and my plan is to setup a Y(T) junction on the airline tube. One way goes to the aquarium and another to the solenoid valve. During the day, I plan to shutoff the solenoid valve and open it during the night. My thinking is that, since there's less resistance on the solenoid valve path, the CO2 will just vent into the room and not reach the aquarium. A no return check valve is also needed on the aquarium path, so that the tank doesn't somehow drain through the other path lol.

Yes this has been done before with a solenoid valve. You must never put a solenoid on the output of yeast CO2 container as in best case pressure will build up and pop off tubes and worst case decorate your room with yeast and sugar mixture.

The only issue reported was the smell in the room from the vented CO2. Someone tried bubbling the CO2 through another bottle of water at night to absorb any odours, but the water did continually go mouldy.

Personally I would leave the CO2 on all the time, keeping it simple, yeast bottle, empty bottle to catch any escaping stuff from yeast bottle (or extra wash bottle), bubble counter, one way valve and diffuser in tank. At night I would turn on an air pump to an air curtain and/or air stone to dissipate and CO2 in the tank. Much simpler and hopefully less smelly.

 

[daskallu]

The only issue reported was the smell in the room from the vented CO2. Someone tried bubbling the CO2 through another bottle of water at night to absorb any odours, but the water did continually go mouldy.

Personally I would leave the CO2 on all the time, keeping it simple, yeast bottle, empty bottle to catch any escaping stuff from yeast bottle (or extra wash bottle), bubble counter, one way valve and diffuser in tank. At night I would turn on an air pump to an air curtain and/or air stone to dissipate and CO2 in the tank. Much simpler and hopefully less smelly.

Nice! The nearby window just gave me an idea regarding the smell. I'll try to run a line from the solenoid valve to window and see if I can avoid choking it.

I'll admit I'm hesitant to try the air courtain / stone route since the aquarium is in my bedroom and I try to keep it dead silent.
I've tried a couple of air stones, eheim balls and even cigarette filters, but I can still hear the hissing sounds.

I'll try leaving it on for the next two nights and monitor the fish and pH. The valve has yet to arrive.

 

[Heelllooo]

Hi,

DYI yeast CO2 question

I've been using DYI CO2 with a T valve for 3 month now with good result.
The valve going into the tank is always open and I close the one going into the room a few hours before light and open it 1h before lights off. When I'm not there I just let the CO2 run all the time but I don't like that.

For me it doesn't smell anything except when I open the bottle to change it.

I think your Solenoid solution is good. Just never close the valve going into the tank ! As said above you don't want to have your yeast bottle totally close or it will explode.

Use a washing bottle with only water, the system is messy and you don't want all the byproduct of the yeast metabolism into your tank.

Also you should look into the Jello method. You can find a lot of recipe online. I'm doing a 300g water / 300g sugar / 4 jello sheet mixture in to a 1.5 Coca bottle, let it cool for like 6h into the fridge and then a bit less than 1L of water / 6 g of powdered yeast / one scoop of sugar above the Jello.
It will last longer with an overall more diffuse reaction.

 

[daskallu]

Use a washing bottle with only water, the system is messy and you don't want all the byproduct of the yeast metabolism into your tank.

Thank you for the tips 🙏.
I used a similar setup with 200g/200ml gelatin solution in a 1 liter bottle, but only added 100ml of water and yeast over it. I think the yeast got drowned to death by alcohol...

Is thr washing bottle used to wash gases too or is it there if the foam gets sent into the airline? I noticed that I only got about 3 fingers of foam at most.