co2 diffuser question

[salvini55]

Ive been reading alot on DIY co2 yeast reactors and would like to build one for my 33 gal planted. The system would have the same reactor as all the diagrams (pop/juice bottles). My problem is the internal python connected to a maxi jet is large and would look bad in the tank. I want to make an external reactor out of two pythons, bio balls and sponge, but dont have a canister filter!?!? could i connect the reactor to a maxi jet output and have it return to the aquarium? If so what size pump would you recommend?
also should i pu the co2 out put at the top of the diffuser or the bottom

diagram
note the sqwiggly when co2 gets beat up by the diffuser lol

[attachment deleted by admin]

[zima]

Wow, this is one twisted set-up you're planning; took me a couple of minutes to figure out! If you insist on pursuing with the setup according to the diagram, you would connect the CO2 tube from the Pepsi bottle to point 2. In other words, you want to send the CO2 bubbles against the return pump's stream. I imagine you would need at least a maxi jet 900, if not 1200 for the stream to be strong enough.

As an alternative, you could construct the the diffuser from a smaller vacuum (python) tube and connect it to a smaller pump (like maxi jet 600) and have it all inside the tank. You could easily hide it behind background plants.

[fischkopp]

I would connect it to p1 (water flows from p1 to p2), at p2 you would risk that the bubbles are pushed out right away. This wouldn't happen at p1, the power head will push the bubbles right into the reactor where they can break down. Depending on the size of tubing and reactor you would be looking for something like an MJ600 or 900.

One important item is missing: you should add a check valve in your CO2 line, just before the reactor, to avoid water flowing back into your reactor bottles. This can easily end up with a flooded floor.

[dan2x38]

I would add the CO2 at the top P1 so the CO2 has a chance of staying as long as possible in the tube. You are right on the money with the water flow. Here is a link to a CO2 set-up I used successfully for along time: http://ovas.ca/index.php?action=gallery;sa=view;id=1073 You will need check valves for sure even on your design. You want to try and protect against yeast leaching into the tank. Also my diagram creates a bubble counter too. You add one bottle mixed with yeast & one plain water to start. After a week mix the 2nd bottle with just water with your yeast mixture. Rotate each bottle every 14 days. This will maintain a stable (close to) output. Hardest thing with DIY is a stable output. Withour stable output you risk algae break-outs if you are fertilizing for increased growth.

Two gravel tubes put together will be a challenge I'd go with a PVC pipe, fittings on each end, and bio-balls. All except for bio-balls the rest can be had at Home Depot.

[salvini55]

Ok so P1 it is. dont worry i plan on putting check valves in and a gas seperator (500ml pop bottle filled half with water, input tube reaching under the surface of the water to separate gas from solids... also acts as a buble counter. the point of getting two gravel vacs is to get the green funnel peice. the second tube will serve no purpose. (they are fitted by compression i hear.)

[zima]

I might be confusing things, but would you not be sending the CO2 bubbles right with the flow if you connect in p1? Where and how would they be mixing with water if they are sent flowing with the stream?

[fischkopp]

I might be confusing things, but would you not be sending the CO2 bubbles right with the flow if you connect in p1? Where and how would they be mixing with water if they are sent flowing with the stream?

One could argue that the bubbles still go with the stream if send into p2

What makes it work is that the bubbles will try to rise, while the power head keeps pushing them contineously down. This will create maximum movement to wash the CO2 into the water and breaks the bubbles down if the hit one of the bio balls.

It doesnt really matter whether the bubbles go into p1 or p2 in the end. There is only a problem with flushed out bubbles if p2 goes immedately back up.

[salvini55]

Thanks for the link dan its the exact set up im going with I have to agree with fischkopp, the more distance from the output the better (higher dwell time). i wasnt sure how strong the pump would be. i dont want to "rifle" the bubbles right out the diffuser without going for a crazy ride first.
i see an error in my drawing.. needs a flow chart!

[dan2x38]

Again concerned with the double conpressed ends of gravel tubes on the outside of the tank. Just take a little built up mulm and the pressure could build inside the tube. Once enough pressure built up pop off goes a cap. If it is anything like Murphy's Law you will be out of the house for the day. Or while asleep to wake to a flood.

I have a gravel tube power head diffuser in one tank. There are plants around it you do not notice it at all. Much less hassle. The cost of two gravel tubes is $10 each. PYC pipe is cheap god maybe I could trade a piece big enough for... I stick on the gravel tube with a Maxi Jet 600. Then place a sponge I cut to tightly fit in the end of the tube. I make a hole in the middle then sick the air line into that hole so it runs up sinside the tube. You can see the bubbles of CO2 churning around and see nothing come out so you know it is working.