DIY CO2, where is it going?

[J. Fisher]

I have attempted to set up a homemade CO2 reactor for my 10g. I used the standard components: 2L soda bottle which contains 3c sugar 1/2tsp yeast & 6c water(or so) conected to a 20oz soda bottle which is used for a bubble counter. It is then conected to a check valve, then to my cheap diffuser: a ceramic air stone. All the tubing used is silicon

After about a day I was seeing about one bubble every one to two seconds in the bubble counter, but nothing coming out of the air stone in the tank. I first checked for leaks but everything is air tight. I was very careful in sealing with silicon at all crucial points and let it cure for 24 hours. I tried switching to a cheaper air stone but that didn't change anything. If I shake the 2L mixture the bps increases and finally I get bubbles in my tank... for about a minute while it goes back down to one to two a second and again nothing coming out in the tank.

I can't figure out were all the preasure is going. I can't be sneaking into the tank because I can see the water go up the tubing almost to the waterline and stay there. Oh yeah I also tried removing the check valve which didn't correct anything.

any clues?

 

[krap101]

sometimes when it is too deep it can be harder forthe c02 to push through

temperature, if it is too low it doesnt produce as much

or maybe not enough sugar (c is cup right) so this probably isnt it

 

[J. Fisher]

Yeah c is cup

I have tried to set the whole unit above the tank to get gravity on my side... nothing. I have put the output at the top of the tank rather than at the bottom... nothing.

I am thinking it might be the mixture or temp or both. I'll try something else. The strange part is the bubble counter showing co2 being produced.

thanks krap

 

[Hoovercat]

use a spray bottle of soapy water to find the leak. It's probably on the bubble counter output side.

 

[Biotoper]

I had a similar problem with my DIY CO2 setup. However, when I raised the output line to just below the surface (without airstone or anything connected), bubbles did come out - so my conclusion was that placing the output deeper resulted in the C02 diffusing into the tank water at the waterline inside the tube, rather than pushing the water to the end and bubbling out, but I'm not sure if that's exactly what was going on. In your case, it does sound like you just have a leak on the bubble counter cap.

 

[hashbaz]

Air stones are not the method of choice for diffusing CO2 into an aquarium. You might want to look into another method - even though it will cast a bit. Airstones are designed for higher volume-flows and higher pressure.

Have you tried taking the airstone off to see if bubbles are making it that far?

 

[malkore]

FYI, a simple airstone will do next to nothing to diffuse the CO2 into the water. You'd be far better off getting an airline reducer and just sticking the end in your HOB filter (assuming you have one). It can be hard on cheapy HOB motors/impellers, but you'll get way better dissolution.

 

[Zezmo]

I have noticed that when I was only running 2 bottles of DIY CO2 that as the formula ran out, there would not be enough pressure to make any bubbles come from my diffusers. That is when they were at the bottom of the tank (about 17inches under water). When I would move them toward the surface they started bubbling again. Once I went to my 4 bottle set up, I seem to always have enough pressure to get things bubbling.

with my old set up I had assumed that the pressure would slowly build and an occasional bubble might be coming out when I wasn't looking. Biotopers suggestion that perhaps at a very low pressure/low volume that the CO2 is just diffusing directly into the water is also reasonable.

 

[malkore]

gravity has zero effect on DIY making it into the tank. it's about pressure, which Zezmo's post is all about. When he decreased pressure on the airstone by raising it in the tank, the pressure from the CO2 could get out.

The only thing you're doing by keeping the DIY jug above the tank is preventing it from siphoning the tank water back into the DIY.

 

[J. Fisher]

As it has turned out, I bypassed the bubble counter and it worked. I know the air stone is a poor diffusion method but I am measering very high co2 levels. So high I have mixed a new batch with less yeast to try and slow down co2 production. I still have not found any leaks on that bubble counter. Oh well, somehow I would like to incorporate that idea but for now it is working without it.

Thanks for the input!