Diy Co2

[Craster]

I'm looking to set up DIY CO2 for a 180l tank. I've had a good look round the various resources in this forum and others, and there seem to be a number of different setups, but none of them seem to match what I want to do. The setup I'm aiming for is as follows:

A pair of two litre pop bottles for the CO2 generation.
Airline running to a T-connector into a water trap to collect detritus
A line running from the water tap to the venturi valve on the outflow of an internal filter
A checkvalve within that airline to prevent water flowing back down the pipe.

I have a number of questions:

1) Will passing the CO2 into the venturi allow it to dissipate into the flow in the tank in an acceptable manner?
2) Do I need some sort of inline reactor to break up the bubbles before they reach that point?
3) Will passing the CO2 into the venturi create suction on the airline, causing the bottles to deflate and collapse?
4) If (for example) the checkvalve blocks, that will cause a buildup of pressure in the bottles. Is there some kind of inline pressure release valve that could be incorporated to alleviate the risk of exploding bottles?

Thanks for your input.

 

[keenonfish]

1) Will passing the CO2 into the venturi allow it to dissipate into the flow in the tank in an acceptable manner?
Not so sure about this but I would guess not - too close to surface co2 would escape
2) Do I need some sort of inline reactor to break up the bubbles before they reach that point?
See below
3) Will passing the CO2 into the venturi create suction on the airline, causing the bottles to deflate and collapse?
No, pressure difference not nearly enough!
4) If (for example) the checkvalve blocks, that will cause a buildup of pressure in the bottles. Is there some kind of inline pressure release valve that could be incorporated to alleviate the risk of exploding bottles?
You could use a tee junction with some sort of rubber cap I suppose - I am just relying on the fact that a daily check is enough and one of the connections would surely fail before the bottle exploded.

Thanks for your input.

The best way I have dispersed co2 into my tank is by using a separate fluval 1+, and running an airline into the side and right down to the hole where the impeller is. Impeller mashes bubbles and they are then sent quite far into the tank. More flow would be more desirable.

The only problem as stated many many times is actually controlling co2 levels and even then it is harder to keep them stable. I am experimenting with various idea's atm...
I actually tried putting stockings over the top of filter housing (filter upside down) catching CO2 - you could see them stretch and raise and lower like those gas containers you get in towns as co2 fluctuated. Anyway I was hoping the water flowing past this reservoir would be more efficiently absorbed but for some reason this didn't work. Not sure what happened to the co2 because if I stopped the filter the stockings would inflate and then as holes enlarged it would release a load of CO2 so I know the stuff was going somewhere. Maybe every so often it was releasing the co2 in this manner without me witnessing it.

But yeah you are going to have fun

BTW If I used three bottles on my current setup I would kill my fish so you will need to work out how to regulate the co2. tbh I think I am going to eventually end up slinging the diy method and go the bottle route

 

[theshadowinc]

I would recomend just going with a presurized system, you will find over time you will actually save money, for me it was costing to much in sugar to stay up with it and I just got fed up with the maintence all the time with it and I see way better resaults from using presurized over a diy method

Cheers

theshadowinc

 

[FishBeast]

I have been bending my mind thinking of ideas for a diy co2 setup and have been contemplating alot of the same questions. I havent made one yet although I have been thinking of perhaps having a fair few bottles... I dont know how many I would need but lets say 6. I would mix my yeast, water and sugar in 2 bottles and then when the co2 production in those bottles begins to wane I would then know when to mix the next 2 bottles. So when i learn how to time it right I would have a cycle of replacing the mixture in 2 bottle lots at intervals which may help produce a fairly constant flow.