Few questions about DYI CO2 with yeast

[daejra]

I have set up a test DYI yeast-based CO2 system with the intention of using it in my 42 L planted tank & I have a few questions (new to the hobby so excuse my ignorance!). I used 1:1 sugar water solution with gelatin (about 400g in total) + another 300ml of water with about 2g of dried yeast mixed in, all in a 1 litre plastic bottle connected to a diffuser with a pvc tube, no valves. Lasted a week so far and there's still plenty of the sugar jelly for the yeast to go through.

1. What is the best way to make the bottle lid airtight? I drilled a hole in the lid, put the pvc tube through and then jammed lots of silicone glue on it from both sides after cleaning all the surfaces with alcohol. At first attempt it did not seal properly resulting in a leak and no pressure build up. Second attempt everything worked fine; I made the hole diameter smaller than the tubing and heated the tube to fit it through; currently CO2 is bubbling nicely through the diffuser, but the seal doesn't seem very durable -- the silicone glue seems to not bond well to the bottle lid. Is there a better way?
2. I have read that some people recommend adding a second bottle to 'clean' the CO2 before feeding it to the tank. How important is this really? Is my thinking correct that this would be to dissolve the evaporated alcohol from the yeast fermentation in the middle bottle before entering the tank? If so I wonder if this is a big effect and whether it is necessary or more of a precaution. Reluctant to add the second bottle because it adds two more potential leak points.
3. Should I worry about regulating the CO2 once I put the diffuser in the tank? I am planning to stock the tank with blue shrimp and neon tetra and I wouldn't want to gass any livestock. It is a 42 L tank so it is pretty small.. I was thinking I should maybe run the CO2 for a few weeks without any livestock and monitor the ph level and if that seems too low, then adjust the volume of the yeast solution accordingly. Does that sound like a good plan?
4. Just hypothetically - what would happen if I didn't supply CO2 to the tank? The plants are mainly monte carlo and hairgrass but I am doing a dry start at the moment and I will have a full carpet before flooding (I have a journal thread for reference). Will lack of supplementing CO2 only stunt growth or can it cause the plants to die off completely? This is my first tank so I don't want to go high tech but I am worried the unregulated nature of the dyi setup might cause more harm than good to the future tank inhabitants..

Thanks!

Here are some action photos of the CO2 setup.

 

[MrClockOff]

Hi there, first of all I think you should start using second bottle as a filter. Otherwise if foam will start building up in the current setup it will get into defuser and destroy it (clog). Second one if you can get those 3/5X Aquarium CO2 Generator Bottle Cap Fish Tank DIY Air Diffuser Valve Guage UK | eBay I’d definitely give it a go!

Cheers

 

[Mike Singh]

Hi Daejra
How are you planning to light your tank? What substrate did you use?

DIY CO2 is very difficult to get consistent results with. Hence, most move on to a CO2 gas cylinder and regulator.

 

[daejra]

Hi there, first of all I think you should start using second bottle as a filter. Otherwise if foam will start building up in the current setup it will get into defuser and destroy it (clog). Second one if you can get those 3/5X Aquarium CO2 Generator Bottle Cap Fish Tank DIY Air Diffuser Valve Guage UK | eBay I’d definitely give it a go!

Cheers

Thanks a lot for the tip! These bottle caps seem like a much better solution than all the gluing I did 😅. I see what you mean with the foam, it did foam up a bit on the very first day but I just took the foam out.. I guess in the long run that would be pretty annoying to deal with so might give it a go

 

[daejra]

Hi Daejra
How are you planning to light your tank? What substrate did you use?

DIY CO2 is very difficult to get consistent results with. Hence, most move on to a CO2 gas cylinder and regulator.

Thanks Mike! The soil is tropica powder aquasoil and the light is a 18 W SunSun ADE 400C LED Light, all the specs and some pictures are in the journal thread that I linked above if you want to check it out. I've been growing the plants emmersed for about 4 weeks now and I have an almost full carpet already, so I won't be needing the plants to grow much more once flooded. Just stay healthy and outsmart algae I suppose!

I imagine a gas cylinder is where I might eventually end up, but reluctant to spend so much on the first tank. Chances are economizing on the CO2 will give me crap results and put me off the hobby.. but I won't know unless I try 😀. So for this first one I am pretty much set on the DYI route.

 

[dw1305]

Hi all,

I see what you mean with the foam, it did foam up a bit on the very first day but I just took the foam out.. I guess in the long run that would be pretty annoying to deal with so might give it a go

We have a thread for you <"Updating an old aquarium, Juwel Rekord 72, and other ramblings">.

........ It seems I had an unnoticed diy jelly co2 incident over the weekend, as the diffuser was full of strawberry jelly and everything in the tank was coated...

I have set up a test DYI yeast-based CO2 system with the intention of using it in my 42 L planted tank & I have a few questions (new to the hobby so excuse my ignorance!).

You don't need CO2, a lot of people don't use it. Have a look at <"Cryptocoryne Parva Carpet"> & <"What is the “Duckweed Index” all about?">, it talks about the "aerial advantage" that floating (or emergent) plants have.

cheers Darrel

 

[daejra]

Thank you all for the advice. I got the bottle caps & added a filter bottle, here is the improved version Very pleased!

 

[MrClockOff]

That's looking much better! BTW I'd throw another idea. You could add check valve on the hose on the bottle with jelly instead of gluing the short hose.

Or this Nylon Pneumatic Control BALL VALVE Hose Tube Inline Push Fit Connector Air Line | eBay

 

[daejra]

That's looking much better! BTW I'd throw another idea. You could add check valve on the hose on the bottle with jelly instead of gluing the short hose.

Or this Nylon Pneumatic Control BALL VALVE Hose Tube Inline Push Fit Connector Air Line | eBay

Cheers! You mean the short hose on the spare outlet? I heated the tube up and pressed down so that it sealed shut, seems to work with no issues for now. Will consider an upgrade like this in case it leaks