Questions about an inline CO2 diffuser

[hulkamaniac]

Not sure if this belongs here or some place else, if so, move it and I apologize. I have two questions about a DIY diffuser I'm wanting to build.
There are two designs I've seen - one is t shaped and the co2 goes directly into one of the t's. The other is I shaped and the CO2 goes in through the intake of the filter. So, here's the questions:

1. Will the T shaped diffuser on the intake of the filter suck more gas than is needed into the water? or could it possibly back up and push water into the co2 tank?

2. Does it matter how long the diffuser is? Is longer more effective?

 

[Purrbox]

Could you supply some links and/or pictures of what you're describing. I'm not entirely sure what you mean by your two descriptions.

2. The longer the reactor the more time there is for the CO2 to be diffused before being pushed out the bottom. After a certain point, additional length won't gain you anything more as the CO2 is already diffused. However if it's too short, then small bubbles of CO2 will escape the bottom.

 

[hulkamaniac]

They are two DIY projects I saw here in the DIY forum.

The T shaped one - http://www.aquariumadvice.com/viewtopic.php?t=88736

The I shaped one - http://www.aquariumadvice.com/viewtopic.php?t=96946

 

[Purrbox]

Okay those are basically the exact same design. The benefit of the T construction is that there is no need to drill or tap a hole in the PVC to input the CO2 in the side. Either one can be put on the intake or output of a canister filter or driven with a waterpump. The CO2 is fed directly into the CO2 Reactor and not the filter. As long as you have a good check valve on your setup then water won't back up into your CO2 Cylindar.

 

[SparKy697]

I think it is also worth mentioning that you want to mount these reactors so that the water flows from the top to the bottom. This will allow the gas to accumulate at the top. As the water enters the reactor it will try to push the co2 down and carry it through the reactor. Physics cause the bubbles to try and resist this motion and try to rise back to the top. The result is more contact time between the gas bubbles and the water. This directly effects the efficiency of the reactor.

As far as length goes, you want it long enough so that you do not carry gas bubble out of the reactor. Too long is better than too short. I have found that if you are using something like an XP2-3 filter to drive the water through, 10-12 inches in length is a good size. As you get to the bigger tanks and feed more co2, you will need to go bigger.

HTH

 

[hulkamaniac]

I will be using this with an XP4 and I'll go with the 10-12 inches you recommend. I'm afraidn of putting it on the intake. I'm afraid over time the Bioballs will eventually pick up detritus and with the diffuser glued shut it'll be next to impossible to get in there and clean it out.

 

[SparKy697]

I gave this some thought too. I think it is a valid question, but I decided that if that became a problem I should be able to reverse flow hot water to clean it out some.

All I can offer at this time is that I have one that has been running since Jan. So far I have not noticed any reduction in flow. That reactor is made with solid pipe so I can not see inside to tell you if its gunked up or not. The one I made with the clear pipe has been running since the posting of that thread and shows no sign of buildup at this time.

When testing on an xp3 I found that I got a little more flow with the reactor on the suction side of the filter. I pumped water into a 5 gallon bucket and timed it for my test.

Something that I had not thought of but seems quite obvious at this time is the fact that you are adding a fair amount of bio filter to the system with the reactor.

I forgot to ask, what size tank is this?

 

[hulkamaniac]

Sorry. I should've mentioned that in my first post. It's a 75g.

 

[SparKy697]

I think you will be happy with a 12" reactor.

Good luck!

 

[hulkamaniac]

Thanks. I'll probably go with the T design and I'll try to hunt up some clear PVC so I can see what's going on in there.

 

[Purrbox]

It's actually not too bad cleaning these out. I just took mine to the sink, filled with water while plugging the other fittings with me fingers and then shook to dislodge the junk. Repeat until the water runs clear. Running water through it in reverse with a good pump should work too.

 

[Alshain]

Yeah I put mine on my intake (pics in my sig) I've changed the generator section a bit but I haven't changed the reactor at all, nor have I cleaned it. The flow hasn't diminished in over a years running.

 

[hulkamaniac]

It's actually not too bad cleaning these out. I just took mine to the sink, filled with water while plugging the other fittings with me fingers and then shook to dislodge the junk. Repeat until the water runs clear. Running water through it in reverse with a good pump should work too.

Cool. That's probably what I'll do. How often do you do that?