opinions on this please!

[purplehaze]

i just built this diffuser for my c02 injection-the water comes from the canister filter and into the diffuser near the c02 line then out the bottom into a spary bar!

[Graham]

Hi, Doesn't the spray bar defeat CO2...it get dissapated/gassed off before it gets into the tank.

A spray bar is probably one of the best O2/CO2 exchange units you can have

G

[Rod]

Some guys who run co2 through a spray bar place the bar under the water level which should help with the out gassing problem.

I might be way off here, but wouldn't it be better to have the co2 entry before the impeller of the canister filter?

Rod:)

[April]

well i have someone doing my 125 for me. a plant expert. he removed my spray bar . so id say not good unless under the water as graham said.

[purplehaze]

the spraybar will be submerged about 2inchs and there is a xp3 aiming towards the xp4 spraybar so its mixing really well in the tank with little heavy curant.
i dont want to run the c02 in to the filter because ive heard it really hard on the plastic.

so does this look like a good design or not?im wondering will the water force its way into the c02 line or is there enough pressure to keep it out?

[purplehaze]

anyone? its hooked up tomorrow.

[Graham]

Carbon dioxide will have absolutely no affect on plastic....It forms carbonic acid in water which is about as weak acid as can be found.

As to water forcing it's way into the line ...you lost me

[purplehaze]

lol sorry...i mean when the chamber is full of water will the water end up going into the c02 tube?

[captain morgan]

Yes, when the gas is turned off, the water will siphon back into the air line and make it's way back to the needle valve,solenoid and the Co2 bottle,all which are bad. I have a similar C02 reactor set up like you. You should have a check valve, preferably brass not plastic on your Co2 line just before the line goes into the reactor, this will stop any water from back flowing past it to the needle valve and Co2 tank when the gas is off. If you have a bubble counter as well- you should also have a second check valve installed between it and the needle valve. Rex Grigg sells these brass check valves and airline specially made for Co2 gas as well. No, plastic valves are not good for pressurized C02 gas nor is regular vinyl airline tubing. I also am running an xp4 & xp3 on my tank and using spray bars on both. One spray bar without the C02 sits at the top of one end of the tank in a horizontal position slightly facing upwards to just barely breaking the water's surface providing movement and air- gas exchange while minimizing Co2 outgassing. The other spray bar which the gas is being expelled through sits below the first one but in a vertical position, in the back corner of the tank and angled towards the front glass of the tank, this seems to create better water circulation to some of the lower areas of the tank as well. Spray bars are great because they expell the water in a larger path and in a gentler flow "not blowing plants over" like the traditional power nozzle does. Spray bars should be below the waters surface when injecting Co2 to minimize outgassing, but you still want some water surface movement even if you only have one.
As to Rod's question you would inject the Co2 into the fiters impeller to break up the gas if you did not have a reactor. This would be my very last choice for getting C02 into the aquarium. The gas can create air pockets inside the filter possibly causing damage to the impeller if it were to run dry or at the very least will make the filter noisy as it breaks up the bubbles and burps them out. The homemade reactor is the best way to go in my opinion, there's no extra equipment in the tank to be seen, it is very efficient, I know because I made my reactor out of clear PVC pipe and I can watch the bubbles get busted up inside- about 95% breakdown - Only a few of smallest micro bubbles can be detected coming out the spray bar. Second choice to a reactor would be a ceramic diffusor, I hear they work pretty good as well but the downside would be, you see it in the tank along with thousands of micro bubbles coming out and rushing to the waters surface, they also need periodic cleaning to keep from becoming plugged up. Sorry for the long explanation, I tend to ramble on when someone gets me going talking about fish- so I hope this helped. One last thing Purplehaze your reactor looks rather short in your picture, mine is 24" tall, and is connected to my xp3. You should also connect it up on the xp3 rather then the xp4 because the flow rate is a little slower and it won't blow the bubbles out before they can dissolve- as quickly, having a longer length reactor would also help. P.S. Hows the weather there in B.C. because here in Alberta it's freakin cold right now.

[Blackwater Aquaria]

Just run it into your power filter suction your impeller will mix it up and you will hardly lose any CO2 I can say that I have CO2 defusers and as long as you see bubbles you wasting your time. All I use is a tank of CO2 regulator bubble counter and a ph controller. Good Luck!!! Mike D. BWA:bandana:

[purplehaze]

thanks everyone!

[Harriett]

I am replying late in the game here but here is my imput. I run my CO2 line with a thru a check valve to a bubbler chamber into the imput pipe of my canister filter [Cascade 1000]; it then goes thru the filter and out to the spray bar which is located a few inches below the surface--[my other big canister FX5 moves the surface water around]. I don't have much of a problem with offgassing--I have a controller and the pH stays at 6.8 without running through my gas very fast at all. I do not have knocking or impeller noises [knocking on wood and tempting the gods for saying this?] but occasionally a bubbling noise at the spray bar if more gas comes out the spray bar that it was expelling--that is infrequent also. I've been running this for 2 years now and haven't had any problems with it...I tinkered alot figuring out filtration and CO2 route for this tank but it's good now.
Harriett