Tricky Co2 Diffusion Question - I Think

[Spiceweasel69]

So it appears my diffuser wont now arrive for another 2 weeks from HK as they sent the wrong item - not even aquatic related.

SO - is there another way i can diffuse co2 into my tank without a diffuser. I cant add it into the filter intake as i dont want the excess noise. I think i have an idea but will need some help.

I have a small glass bowl that i can turn upsode down in the tank and feed my airline into it, therebu creating a chamber of co2 that can diffuse into the water. I bought a JBL permanent test kit as my drop checker hant arrived either but it only reads to KH of 16, where mine is 20 - doh.

Anyway, the amount of diffusion will be proportional to the area of contact of water and co2 within the chamber. If i dont put too much gas in, the area and absorbtion will be lower, and the more i put in, the greater area and absorbtion. The only real problem i have is measuring how muchshould go in to start with and what rate to keep the flow at - i guess itll be trial and error. Does this sound like a decent temporary measure?

 

[shahrezsyed]

nice plan. but dunno anytthin abt this stuff.am also researching for a planted biotope.
cheers
shahrez

 

[BenPursglove]

I'd wait until you have the diffuser rather than trying to rig something like that up as you will also need some sort of turbulence inside the bowl to get diffusion. Having said that it may work, I dunno. There have been some seemingly good home made DIY diffusers I have seen on youtube. The difficult thing is to keep the CO2 at a stable level which is what we are looking to achieve in a planted tank.

That's a high KH/CH you have there! Water round here is considered to be hard and I have KH of 8 out of the tap. Best thing to do in that case is get some 4dKH water from AE or make your own. This way you have a stable controlled measure of CO2 @ 4dKH to measure against the JBL colour guide. There is a cool pin on some other forum <cough>UKA<cough>PS<cough> about this but I don't think I can link to that here.

 

[Spiceweasel69]

Iv went ahead and improvised - seel below.

The co2 was filling the inverted glass, as you see now approx 30% has already absorbed into the water. I will wait for the rest to dissolve and then set the co2 going again, filling the glass with one small bubble per second. Soon an equilibrium will be reached where the uptake of co2 into water (with 100% efficiency) and injection into the tank becoming stable.

I will retest KH as it does seem v v high, but then the rock in the tank bust be limestone - or a form of.

 

[fatheadminnow]

...I will wait for the rest to dissolve and then set the co2 going again, filling the glass with one small bubble per second. Soon an equilibrium will be reached where the uptake of co2 into water (with 100% efficiency) and injection into the tank becoming stable.

Your idea seems pretty neat, but one thing I would worry about is over dosing with Co2.

1 drop per second is a good starting point, but that will varying from tank to tank, and the only way to figure this out is by using a Co2 drop checker.

If you allow an equilibrium to be reached, that equilibrium might be more than the 30 ppm of Co2 that we want. Which would be bad.

I like your idea, but I would wait until your Co2 drop checker arrives, that way you will know how much Co2 is in the water.

-FHM

 

[BigC]

I think I have an old JBL one lying around

 

[Spiceweasel69]

Hey - ta for the replies. The tank is 600 litres. I would think an equilibrium would be reached at around 15-20ppm. Fluval fx5 is creating a decent current to assist diffusion. If it was a 200 litre tank id think again. I will see what the JBL permanent co2 test comes up with in a few hours. Will let you know.

 

[keenonfish]

Hey - ta for the replies. The tank is 600 litres. I would think an equilibrium would be reached at around 15-20ppm. Fluval fx5 is creating a decent current to assist diffusion. If it was a 200 litre tank id think again. I will see what the JBL permanent co2 test comes up with in a few hours. Will let you know.

How do you actually work out at what point equilibrium occurs?

 

[Spiceweasel69]

Hey - ta for the replies. The tank is 600 litres. I would think an equilibrium would be reached at around 15-20ppm. Fluval fx5 is creating a decent current to assist diffusion. If it was a 200 litre tank id think again. I will see what the JBL permanent co2 test comes up with in a few hours. Will let you know.

How do you actually work out at what point equilibrium occurs?

It will be the point where the amount of co2in the glass does not grow nor reduce