Using two diffusers from one neddle valve and one bubble checker

[papa_c]

I've just set up my tank which consists of two Eheim 2215 the in takes are in the back corners and is fed back into the tank via separate spray bars. CO2 is injected via an inline diffuser in only one of the spray bars. My thinking is that this would give an uneven distribution of co2 in the tank so my thought is to use a T-piece after the bubble counter fed two diffusers.

What problems do you see this causing? And importantly would it work?

 

[Claire]

You will end up with more gas in one than the other as the lengths of pipe will not be identical and the pressure in the inline diffusers will be different. This wouldn't cause a huge problem though as all the gas is going into the same tank, so ending up in the same place anyways. For more even split of the gas you can just get another needle valve and have one for each side.
I doubt having it split with just 1 needle valve would cause much of a problem until one inline diffuser starts to clog up slightly, and then most of the gas will go through the lesser resistance route of the other side, so you end up with one-sided gas. Since it's all going the same road then it's not as big a deal as when people try to do the same but to 2 different tanks, so one tank ends up gassed and the other gets nothing, but you will start to get a little distribution problems.
If it were me, I'd try it with just the one needle valve first and see how it goes. If the distribution is obviously uneven between the 2 sides then you can just get another needle valve and put the 2 of them after the split.

 

[tim]

Also worth making sure your reg has enough oomph to run two high pressure diffusers.

 

[papa_c]

Gents, thanks for the answers sorry for the typos must have been still asleep!

Good food for thought, on the regulator point does if I need 35psi to run one diffuser would I need to crank this to 70psi. Is it that simple?

not sure I would be comfortable with 70psi in the plastic bits of equipment as there is no maximum rating on them.

If one diffuser becomes blocked this would result in more than 35psi to the other diffuser. Would this affect how much co2 pushes through? Or is my understanding of the theory flawed....

 

[EnderUK]

You would set you reg to 35psi since you'll be running the diffuser in parallel. If you were running the diffuser in series, don't know how you would do this, then you would crank up the pressure. Pressure is like voltage in an electrical circuit, flow is like current.

 

[papa_c]

Thanks......looks like it will be a T-piece and a second diffuser will be the way forward....

 

[Iain Sutherland]

i tried this a long time ago and it causes a lot of headache, you will have one diffuser work and the other will do very little making it hard to gauge how much gas is going into the tank, it will also fluctuate wildly depending on how full the co2 tank is. Gas does funny things when it has more than one path...
2 needle valves is really the only way forward and even then has complications. It is easier with intank diffusers than inline ones though which require the high pressure.
A better option for what you are doing is one full length spray bar with fewer holes and the second spray bar with inline in the middle.

 

[Doug]

Interesting thread. I am about to set up a tank with two separate canister filters and am going to have the CO2 via an inline diffuser on one of the filters. My question is - does it really make that much of a difference having all the CO2 via one spray bar..?

Is it no difference than having only one CO2 diffuser in a tank?

 

[Iain Sutherland]

Shouldn't do too much, as long as your co2 levels are good and distrubion effective. It will help to have the non co2 inlet on the co2 side...
If co2 level is good at lights on then like an inline it shouldn't be an issue.
However if co2 levels are not ideal then you may find one side growing better than the other. I had this issue with Asian dreams and used to switch the reactor to a different filter each time I cleaned the pipes.


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