Dual venturi DIY External CO2 reactor

Gerryd

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Mike-B,

Thanks for the confirmation! I feel better:D

It does work a lot better. I can see the difference via pearling and that my c02 turns off more often than before to get to the target.....

I think the AM 1000 is a good reactor IMO.

I run a 500 gph pump to drive it (Tom's tip) and it is only 12" of flex hose between the pump and the reactor, so the flow through is excellent. The outlet is stuck right into the sponge for the 1800 gph return to tank, so I think the c02 is well chopped and distributed!

Am still playing with c02 rates as my drop checker is still blue:(

Thanks again to all!
 

Tom Barr

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I watch the plants, if strong pearling is evident, do not worry, after about 1-4 hours in to the light cycle, if you have good pearling, that's about right and what you want to see.

At lower light, maybe the last 2-4 hours will pearl, even in my non CO2 tanks, I have good pearling.

Regards,
Tom Barr
 

rubb

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Thank you Tom about such an simple but effective design :)

I have 2 questions:
  1. what is minimum GPH of filter pump for this reactor to effectively work? I have ~50G tank with JBL Cristal Profi 250 external filter ( around 100GPH ).
  2. I hear people that they hear noises coming from reactor... is it really noisy? May be noise is only when CO2 is being injected, or noise is from water flow? My aquarium is in bedroom, so it is important for aquarium stuff to work quiet.
 
M

mrkookm

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gerryd said:
The outlet is stuck right into the sponge for the 1800 gph return to tank, so I think the c02 is well chopped and distributed!

Am still playing with c02 rates as my drop checker is still blue

Your problem with the DC remaining blue is due to too high a flowrate, reduce this by more than half for best results. I have a 1900GPH pump and I reduce mine to 500~600GPH and my DC is limegreen anything higher and my DC will be blue even though lots of mist will be in the tank.

rubb said:
I hear people that they hear noises coming from reactor... is it really noisy? May be noise is only when CO2 is being injected, or noise is from water flow? My aquarium is in bedroom, so it is important for aquarium stuff to work quiet.

Noisy....well if you put your ear directly on the PVC you will hear the churning on the inside but I would'nt classify this as being noisy. This isn't audible standing back or mounted normally, well at least not IME and I truly doubt a canister filter will provide the flow required to produce this 'noise' you heard about anyways.

I am using an external 300GPH pump to power my reactor. Since it's only powering my reactor I have barely any head-loss as opposed to a canister with all the extra media therefore I am pumping more water @ a higher pressure causing more intense churning and I don't hear anything ;) so If there was noise I would have certainly have heard it because of my setup. I am very sure you will not hear any such noise with yours...it's an excellent reactor that gives great results....try it :D
 

Gerryd

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Hi,

Thanks for the reply, but.....


I am only using a 500 gph to run the reactor. The 1800 gph is for the ENTIRE tank. The outlet FROM the reactor goes into the 1800 and back to tank.

I am a little confused by your answer as others here had recommended the increase from what I had.....

When you talk about reducing flow rate, which flow rate do you mean?

Remember that my tank is 180 gal, so reducing the pump outflow by 50-60% will have a detrimental affect on my tank..........


Appreciate the help.
 
M

mrkookm

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Hi,

Thanks for the reply, but.....


I am only using a 500 gph to run the reactor. The 1800 gph is for the ENTIRE tank. The outlet FROM the reactor goes into the 1800 and back to tank.

I am a little confused by your answer as others here had recommended the increase from what I had.....

When you talk about reducing flow rate, which flow rate do you mean?

Remember that my tank is 180 gal, so reducing the pump outflow by 50-60% will have a detrimental affect on my tank..........


Appreciate the help.


I know the 1800GPH is for the entire tank but that is way too much flow and half of that amount would be a step in the right direction while still maintaining a 5 x turnover rate. Correct me someone if I am wrong here but I also think contact time with mist is also important. IME when I turn up my flow the mist in my tank move all about so quickly with zero contact time and it's a waste, I reduce my flow and voila! My plants pearl like crazy and my DC changes color in no time. If you are going to continue using that much flow you would be better off using a mazzei injector, at that flow rate the force water going through the injector should diffuse the co2 rapidly and raising the Co2 needed at that flow quickly.

What kind of tank do you have that requires this much flow is it mostly big fish or is it planted? I know of others who has bigger than you and use less flow, you do not need 1800GPH on a freshwater tank unless you have a couple stingrays and sharks? :)

Maybe TBarr can chime in more on this issue? I'm also a little curious of the turnover flowrate that is used
 

Tom Barr

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rubb;20429 said:
Thank you Tom about such an simple but effective design :)

I have 2 questions:
  1. what is minimum GPH of filter pump for this reactor to effectively work? I have ~50G tank with JBL Cristal Profi 250 external filter ( around 100GPH ).
  2. I hear people that they hear noises coming from reactor... is it really noisy? May be noise is only when CO2 is being injected, or noise is from water flow? My aquarium is in bedroom, so it is important for aquarium stuff to work quiet.

1.I'd run 200gph or so
2. No, not much. Work on making the inside of the stand quiet also(padding, insultation materials, rubber etc).

Regards,
Tom Barr
 

Tom Barr

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I'll be using 1600gph or so on my planted tank that's a 180 gal.

I can always reduce flow with a ball valve.

The wet/dry will run about 800gph.
Canister will run about 800gph.

Heater is in the sump, and the CO2.

UV in the canister loop and the Tee for back washing the filter/draining it, and for the tank drain.

Backing off the flow suddenly will always show pearling.
O2 can accumulate and diffusion is slower with less flow, does not imply that there is less/more growth however over time.

You would need a total O2 production curve over an entire day to see the differences.

But if you get good pearling and like the slower flow, and it gets the job done, then that's what I'd suggest sticking with.

That is what you want and you can see that, better than any test kit or ppm's reading. Flow can blow that off while still producing higher growth rates, thus you cannot tell as easily.

More growth is not always better, but I think a good visual cue it more important as long as algae and good over all tank health is good.

Regards,
Tom Barr
 
M

mrkookm

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That is what you want and you can see that, better than any test kit or ppm's reading. Flow can blow that off while still producing higher growth rates, thus you cannot tell as easily.

More growth is not always better, but I think a good visual cue it more important as long as algae and good over all tank health is good.

So as long as their is lots of mist all about even though visual pearling is not seen until flow slows and DC remains blue, Co2 levels can be assumed good?
 

Gerryd

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Hey mrkookm,

1. Remember that my head height is close to 5' so, only 1200 gph at that level :)

I used to have two 500 gph pumps, but Tom had suggested going higher. I chose the 1800 gph as it was not much more $ than the 1200, and with the ball valve I knew I could reduce if necessary......

2. I do get good pearling within 1-2 hours of lights on and it is very obvious, so the DC color is not as important to me, as the other visual clues as per Tom's earlier response. Tank is very healthy.......

3. My fish DEFINITELY like the higher current. They spend most of the day swimming against it in large schools, which I like :)

4. Planted community tank with several hundred small tetras, corys, dwarf cichlids. No big fish, rays, or sharks :).

I am now curious about the reduced flow and will try it later for a few minutes and see if there is a difference in pearling..........

thanks for your replies
 

Tom Barr

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I think it's a huge myth fish do not like higher currents.

They get fat, lazy, just like us.
They do not look as nice, they do not behave like they should, they do not eat nor grow as well either.

Like us after exercise, we are alive and hungry.
Some use powerheads for 2-4 hours a day/at night etc to exercise their fish.

They want rest, they can wondering into the plant beds.

Regards,
Tom Barr
 

Gerryd

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I agree..... I have almost always had > current than conventional wisdom dictates for my size tank at the time and have never had issues.....

You can see when they get tired, they just drift into a quieter area.

My fish like to swim against current and then RIDE the current back to other side and start over in a loop.....they do this for hours and fish join/leave as desired.

I did some reserach on the Mazzei venturi.

Question:

Where in the flow is this placed?

Thanks,



conventional wisdom BTW is somewhat of an oxymoron, like 'government intelligence':rolleyes: , but don't get me started on THAT thread lol........:D
 

Tom Barr

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G-
You place the mazzi many places, depends on if you want the mist of the dissolved CO2 effects.
Generally folks add it near the top of the return line and they make a Tee off the main line with some ball valves to throttle flow in/out of the mazzi loop.

You can adjust it so that you get more/less mist to suit.
I like mist, think it really makes the tank pearl well and keeps things clean and perky.

But it's nice to do this, and then for photo's, stop and adjust it.

Regards,
Tom Barr
 
M

mrkookm

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I used to have two 500 gph pumps, but Tom had suggested going higher. I chose the 1800 gph as it was not much more $ than the 1200, and with the ball valve I knew I could reduce if necessary......

I see the reason now and at least you have the ball valve if necessary.

[/quote]2. I do get good pearling within 1-2 hours of lights on and it is very obvious, so the DC color is not as important to me, as the other visual clues as per Tom's earlier response. Tank is very healthy.......[/quote]

This is a little different for me regarding the pearling, I get little to no pearling at all and I have lots of mist around but as Tom stated { Flow can blow that off while still producing higher growth rates, thus you cannot tell as easily.}. I often wondered if this was possible even though my DC was blue but now I have confirmation that high flow and misting still gives plants needed Co2. I must say having a lower flow versus higer shows a ridiculous difference with pearling and like you with the higer flow, the lower flow is giving me great results, plants are happy and I have no algae.

3. My fish DEFINITELY like the higher current. They spend most of the day swimming against it in large schools, which I like :)

4. Planted community tank with several hundred small tetras, corys, dwarf cichlids. No big fish, rays, or sharks :).

I see you're tank is more in tune for your fish while mine is more plant oriented so more flow is in your best interest.

It is interesting to note that Tom apparently uses 2 pumps in his setup, one for overall turnover ' the sump' and the internal flowrate 'canister & UV on closed loop'. Still a big difference in my eyes as his co2 gets circulated in his tank longer 'max contact time' even though he is @ 1600GPH...sounds efficient don't you think?


I did some reserach on the Mazzei venturi.

Question:

Where in the flow is this placed?

Thanks,

It is placed on the return line, I woul dthink closer to the pump as possible.
 

Tom Barr

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Yes, the idea I have is FASTER current, turnover times, more responsive CO2.

I really do not care much about the little I lose to some surface movements, so what?
As long as the surface is not breaking, I'm fine.

I have a wet/dry, but the over flow box is sealed, as is the dry part of the box, no CO2 can escape there.

If you have high fish loads, it pays to have high flow rates, if your fish loads are small to moderate etc, then you can definitely get away with less, but not too little.

The problem here is the plant biomass, structure of the layout and the flow rates/patterns in the tank used to make comparisons, I'd suspect they are quite different for each tank we are discussing.

By being able to adjust things later, we can change them to optimize the tank for both plants and fish.

I use to be 100% plant, but the last 3-4 years I've moved back to center and focused more on the first love I had in this hobby: fish. So I weigh the fish and plants equally, this works well also. Same with methods, I weigh non CO2 and CO2 methods the same. Reef vs macro algae and so on.

Now, back to the topic at hand here, the DIY venturi method.



Regards,
Tom Barr
 

fjf888

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I saw in the previous post that the PVC you used in your example was 1ft long. For my 72g should I cut the two foot piece down to a foot or 18" or is the height largely irrelevant?
 

Tom Barr

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Unless you are really pushing higher flows than say 400gph through there, 12" should do it.

Regards,
Tom Barr
 

fjf888

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Count me as another believer in your reactor. Per your suggestion I purchased a 300gph pump to power, ran the outflow to my main 500gph pump in my sump. I'm not entirely sure about the venturi, but I simply looped from the reactor to the pump output. Is this effective enough? I do get a small occasional mist of bubbles, most of the time there is nothing to see.

It works fast, (I have my CO2 timed with my lights) within an hour all plants (except the lowlight plants) in my tank are pearling, I have a pH drop of about 1 . I might build another reactor as this one has a very small leak between the bushing and coupling, and I put no bioballs in, but even with these caveats it is extremely effective.


Thank you for your help and coming up with this design.

Fred
 

Gerryd

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Fred - sounds like you have it working correctly........I'd be curious if it works better if you use bioballs later.........

This has worked well for my AM 1000 modification as well and was simple to do :D

My drop checkers both show 6.6 so I can really tell that this works. Nice green color:D

One thing I noticed and was curious about re: the flow required to drive the reactor.

I came home today and my reactor was almost empty of water.
Only the bottom 1" out of the approx 12" total length contained water. This was NEVER the case previously, but I did recently INCREASE the amount of c02 input.

Turns out an air bubble had formed in the reactor pump and reduced the flow of water to the reactor.

I knew this could happen with a canister (from other threads), but thought that this type of pump was somehow immune (don't ask), but I guess the impeller is right there so I shouldn't be surprised.:eek:

ANYHOO...

I removed the venturi loop for a second and eliminated the air bubble and all was fine with the flow......

BUT

The pearling of my tank was HUGELY IMPROVED during this time frame. Pearling occurred within 30 minutes of lights on vs 90 mins prior....and the evidence of pearling from the bottom of the tank was tremendous and overall much increased all over the tank....

1. Was this increased/better pearling caused by the reduced flow in/out of the reactor?

2. If so, should I use a smaller pump to drive the reactor? I use a 500 gph Mag drive to run it now. I would say the flow was reduced by at least 50% during this time frame..........

3. Do I want to somehow have LESS water in the reactor?

I thought that MORE flow to the reactor was better????


BTW, I never thought I would see such levels of c02 with my setup (overflows, wet/dry, etc). Awesome.

Thanks again to all for your advice and patience.

P.S EI after 3 weeks shows a marked improvement in plant growth and health/color. Thanks again!
 
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fjf888

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Mine is working well, even though my DIY skills are weak at best :)

I am far from an expert as you know, but my guess is, and , I think Tom covered this earlier ,was that the higher flow rate may reduce the appearance of pearling, but the same rate of photosynthesis is taking place, the flow of water itself may drive off some of the O2 bubbles.

Ironically I think one of the main reasons this reactor is so much more effective is increased flow. In tanks the size of ours the advice I received of having these puny powerheads is probably erroneous. I think the increased flow disperses the CO2 throughout the tank much better

Fred