Diy Co2 Kit...i'm Stumped As To Why This Wont Work!

[trojannemo]

hey guys.

so i'm trying to run 2 bottles (for now, 3 soon) together for my DIY CO2 kit.

i have both bottles connected to a T connector, which goes into the tank.
between each bottle and the t-connector there is a pressure control valve.
i can close one, and open the other, and CO2 will flow into the tank. this works with either bottle.
so if valve #1 is open and valve #2 is closed - it works
valve #1 closed, valve #2 open - it works
both valves open...nothing. no water gets sucked into the bottles, but just the same no CO2 ever makes it to teh tank. i've waited more than 12 hours to see if anything would happen and it doesnt.

i have the lines from the bottle to the T-connector taut, so that at least in design, the gas has nowhere to go but "up."

there are no leaks, otherwise what i mentioned before wouldn't work either...

so why can't i get this to work with both valves (i.e. both bottles) working together?! i've seen this type of connection in many instructions online and it apparently was working for the authors...

so i'm stumped...what is it? what am i missing?

 

[Lateral Line]

When you have one valve open is there plenty of flow or just enough to allow the gas to reach the tank? Is the line into the tank open or is there something on the end that would create a back pressure? Are each of the two valves seeing the pressure from the other and backing off?

What sort of valves are we talking about here?

 

[Behold]

A Picture of the setup and the valve part would help it might be a simple mistake?

 

[SuperColey1]

I ran 3 of these into a gang valve with a Rhinox diffuser before I went pressurised and it worked a treat as far as DIY is concerned. The Rhinox would create plenty of back pressure so the rest of the kit has to work really well to be able to counteract this pressure.

Plastic T pieces however can be pretty dodgy for leaks.

If you are not seeing any residue climbing from the pipes from the bottles then the bottle has a leak or the mix isn't working.

As above pictures of your setup along with a detailed description of the mix you use plus type of diffuser would be superb and get you much better answers.

AC

 

[trojannemo]

here we go.

i thought i had explained in this in the first post. there are no leaks. how do i know? because i can get either bottle to pump CO2 to the tank if i just close the other bottle's valve. as soon as I open both valves, co2 just stops going up. water doesnt get siphoned either.
i am planning on a third bottle, and on a gang valve, but that will have to wait till i have the time to go to the LFS. i dont see why this setup isnt working because it's just as i've seen it online!

for the mixture - at first i was using the following proportions:

I mix 3/4 cup sugar, 6 cups water and a pinch of yeast (roughly 1 teaspoon does the trick).

but that mixture would only last 5-6 days for me.

so this time i decided to try this other mixture:

pour 2 cups of sugar into the bottle. Add 1/4 teaspoon of baker's yeast and a pinch of baking soda.

this new system was slow to start and doesnt have as much punch, but it seems as it'll last longer.

if you have any recommendations on a better mixture, i'm all ears.

but right now my main concern is getting both damn bottles to work together.

 

[SuperColey1]

With your light get 3 but thats a side issue.

Your reasoning is a little off. Doesn't matter about it lasting longer. You awnt peak strength not longevity.

You don't need both working together. They need to be overlapping so while 1 is at peak the other is starting, while 1 is dropping away from peak the other is getting towards peak etc. In other words its like a dice:

All opposite side combinations = the same (7)

If 1 is facing you then 6 is the other side, if 2 is facing you then 5 is the other side etc.

If 1 bottle is at 0% then the other should be at 100%, when one drops to 80% you want the other to have reached 20% etc. Then you have consistency. This is why it is so hard to achieve consistency with DIY.

Was the previous mix working? If so I would go back to that one and use it with 3 bottles.

Just searched through an old journal from when I used 3 bottles and this was my DC:

I think I was using 1½ teaspoons of yeast (measured not normal teaspoons, 1½ cups of sugar and filled my bottles up to where they start to bend. about 3/4 I would say. I then put some big thick hiking socks around them.

To check for leaks wipe some washing up liquid around the joins - T pieces valves etc and if there is a leak you get bubbles.

AC

AC

 

[Lateral Line]

i thought i had explained in this in the first post.

... but not well enough! You didn't answer these questions...

When you have one valve open is there plenty of flow or just enough to allow the gas to reach the tank? Is the line into the tank open or is there something on the end that would create a back pressure?

... I can now see the type of valve you are talking about so my last question is no longer relevent. It takes pressure to push the water out of the tube in the tank, more if there is some kind of diffuser on the end, that is why that is important to know. The flow rate is also important to know as it gives an idea of how vigorous your reaction is. If the reaction is slow, it will take time to build up the pressure in the delivery pipe to the point where it can flow into the tank, with both valves open, the volume of the system that needs to be pressurised is much higher so will take longer.

 

[kenny fish fanatic]

hi could i sugest,buying some new yeast as it dies with age,try staring it off in a cup.half cup of,lukewarm water,1 teaspoon sugar 1 teaspoon,yeast,cover it with clingfilm,it should start in an hour or so,then add it to your water in your bottles,it should work,for weeks,good luck,

 

[SuperColey1]

i thought i had explained in this in the first post. there are no leaks. how do i know? because i can get either bottle to pump CO2 to the tank if i just close the other bottle's valve. as soon as I open both valves, co2 just stops going up. water doesnt get siphoned either.

The logic of this suggest a leak to me!!! What should happen is when you add the changed bottle and open the valve, the first will send its gas to the lowest resistance which as the fresh bottle has just been opened, close, reconnected and then the valve opened will be the lowest resistance. Once the pressure has built up within the new bottle again then the gas will be forced back towards the diffusor. There must be a leak or a problem somewhere or one botle is not creating enough pressure within itself to make the gas go in the diffuser direction.

Think of it like this:

If I gang valve my pressurised one to go to the diffuser and the other to go to a coke bottle then because the diffuser has back pressure the gas will all go down into the coke bottle. Once the coke bottle has been filling with gas for a while and has built up more pressure than the back pressure of the diffuser then it will be forced to go to the diffuser!!!

AC

 

[Bungy]

I use two bottles, works fine. I run my airline tube directly into the tank and into the filter INTAKE. This is then suitably diffused by the pumps impellor and squirted back out through my spray bar (pointed downwards to maximise CO2 into the water). This certainly makes a difference to the plants - even a simple DIY system like this. If I get lazy and let the co2 run out then I notice a significant die-back of some of my plants. Make another mix and within a couple of weeks I can see the difference.