Dual venturi DIY External CO2 reactor

[scottward]

Photos? Part numbers?

Out of interest, how far do you have the bleed tube into the reactor? i.e. do you allow some gas build up at the top of the reactor or none?

If you aren't allowing any gas build up, I wonder if the reactor is essentially doing nothing - the gas is essentially completely bypassing the reactor and misting directly into the tank?

I recall that Tom mentioned right at the start of this thread that you can choose how much gas build up you want by changing how far the bleed tube feeds down into the reactor (or by putting the bleed line somewhere on the side of the reactor; obviously it can't then be changed).

It would be nice to pair up a pump and reactor and 'shrink wrap' the design for sale....

Gas build up in the reactor is a PITA as, if there is a powercut, the gas can make it's way into the impellor of the pump and cause it to run dry. You don't need much of a gas build up at all to do that. However, mitigating this issue by using the bleed line and misting the gas through the reactor may essentially be bypassing the effect of the reactor altogether by considerably reducing the gas/water contact time inside the reactor (which is obviously the whole point).

I have a swing check valve that I plan to fit between the pump and the reactor when I get around to it.

I think that perhaps this combination, and not using the bypass line at all, might offer the best performance from the reactor when configured this way?

I think a lot of people are overlooking the powercut issue etc when running these reactors like this.

Scott.

[scottward]

If you aren't allowing any gas build up, I wonder if the reactor is essentially doing nothing - the gas is essentially completely bypassing the reactor and misting directly into the tank?

Maybe my thinking is fundamentally flawed.

Maybe if all the gas the enters the reactor does go through the pump impellor and get misted back into the reactor it will dissolve 'as good as it gets' anyway...? My reactor is filled with plastic balls (can't remember what they are called), these are designed to provide turbulence, hence break up the gas into bubbles that are as small as possible.

Here is a thought - perhaps, rather than feeding the CO2 into the reactor, the CO2 line should just go straight into the intake of the pump in the first place? If the pump shuts down, but nothing else does, I suppose there is still the chance of a dry run situation, but I suppose you can't protect against everything...

[anteleon]

hey scottward,

nice to meet you mate.

As for your question about the bubble of gas at the top of the reactor, its funny because i actually dont know even if there is one, because my reactor body is regular PVC, not clear, so i can't see the bubble. I put the venturi/bleed tube only a tiny length into the reactor incase I only had a small bubble of gas at the top of the reactor. I would say maybe 1/4" of an inch into the reactor. I think mine is running correctly as far as i know, i will be testing it with some clear PVC soon to try to figure what is going on inside
the reactor a bit more.

Heres the part numbers, from REECE irrigation department. (note: these parts in total cost me $50-$60 AUD dollars, so the reactor parts for my build are quite expensive compared to Tom's which came to around $15 USD. But these parts were the only alternative i could get get to make the reactor from parts sourced here in australia.) Also my RESUN pump was quite expensive going for around $90 AUD, however as you will read froom my previous post i had troubles using a 1000LPH pump with this rector build.

1507940 - Poly Threaded Bush 4162 - 50mm x 20mm ( i got 2 of these )
1508005 - Poly Threaded Nipple - 4222- 20mm ( 2 of these )
1508125 - Poly Threaded Socket - 4366 - 50mm ( 2 of these )
1508326 - Poly Threaded Elbow M&F - 4692 - 20mm ( 2 of these )
1507940 - Poly Threaded Bush - 4162 - 50mm x 20mm ( 2 of these )
1405510 - Dwv Adaptor Pvc X MI - 50mm ( 2 of these )

I also used 20" of 2" PVC pipe (regular, not the clear stuff)

Resun Utility Pump 2600LPH that has threaded sockets for 19mm irrigation fittings (so you can just screw in the 19mm fittings into the pump outlet and use standard 19mm flexible irragation tubing for the remaining plumbing to the tank etc) [on the box the pump is rated for 3000LPH but i think the actual output is only 2600LPH i've read] If you get gas lockup while using smaller LPH rated pumps than this one, try a larger LPH pump. ( i think thats the case anyway )

Bunnings stocks the 19mm fittings, 19mm irrigation tubing and the 2" PVC pipe, i think the pipe is sold in 1 meter lengths there from what i can remember.

Pictures:

(coming really soon sorry my current camera phone is shocking, when i get my iphone back i will retake the pictures.

thx,

anteleon.

[priv_sim]

Correct..... Whether you have an external pump or not this config is always recirculating the Co2, truly mixing it in and dissolving it before the enriched water gets pumped out to the tank.


See the drawing below where I have inserted DIY venturi for optimal performance as well as placement of venturi output as suggested by TBarr. If an external pump was used the basic venturi would be inserted somewhere along the suction line so that impeller would dissolve more co2.

I'm not familiar with a canister filter or its inner workings but some guys on PT.net has suggested to remove the impeller in the canister and use a dedicated external pump to do all the work...... see here

Hi!

Could someone explain me how "DIY basic venturi" is made?
Will this system reduce flow rate of external filter? (400gph filter)

Thanks in advance!

[samh]

I experienced gas lock with the 1000LPH pump after increasing the flow rate of CO2.
With the 2600LPH pump i can really increase bubbles per second through the reactor and not get lockup!
Misting, i love it, i know you dont need it, but it helps put my mind at ease as it indicates the reactor is working. I have standard PVC pipe and can't see inside my reactor so the mist helps with that.
Why would you want to decrease the misting with a flow restricter valve? I love misting!!!!!!
If the venturi is not working, try putting the venturi tube intake side VERY close to the impellor, as close as you cant get, this should get the venturi working as it should.

update: drop checker is almost yellow, or yellowish, i think mission successful, objective achieved.
With this reactor, high light, poor mans equilibrium, EI and a 50% water change every week, i think im going to see some really really nice growth.

abit off-topic now, but,

Tom Barr, any chance of a patent with this reactor, i would love to sell these reactors and the yeast ones here in australia under your brand, i think theres a huge market for them.

cheers all,

anteleon.

Hi anteleon,

Glad you found the parts ok. Haha i had a different problem, i made one similar but the only pumps i had were a rio 1100l/hr diy NW and a 3000l/hr rio hyperflow, since i wanted to use my 1100 rio NW as a separate mister i had to upgrade my reactor, because the 3000l/hr one just blew the bubbles straight out the end haha.

I ended up using 100mm pvc about 300mm long filled with bio balls, since i had the NW i didn't bother with the venturi because there's no way it'll ever lock up

I tried selling the 3000 so i didn't need to make another reactor but i couldn't ha.

[pgaks3]

just read through this thread, i like the design, im pretty sure i understand how it works, but i do have a few questions:
1. can this be scaled down to a 10g tank? i am planning a high tech 10G, my reasoning on going high tech is i want a carpet of dwarf baby tears, and it seems co2 is the only way to keep them happy.

2. any suggestions for a small enough external needle wheel pump/powerhead to use for this?

3. can this be used with DIY co2? I am planning on the 2 liter bottle with a 1 liter bottle after it to catch any yeast that gets sucked in, willing to go up to 2 bottles if more pressure is needed.

tank is a 10g all glass, filtration is 501 canister filter, lighting is a single 18w t8 now, but plan after the new year is to switch to 2 cfls horizontally mounted with diy reflector or 2 par30s.

thanks in advance

sheb