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Tiny super efficient CO2 reactor

302K views 380 replies 156 participants last post by  jasonvthomas 
#1 · (Edited)
Go to any Petco and buy this tiny internal filter:
http://www.petco.com/product/13796/Hagen-Elite-Mini-Underwater-Filter.aspx

In the box you will find everything needed to make an extremely efficent in-tank Co2 reactor:

1. Discard the tubing that supplies air to the filter and is meant for aeration, you don't need it.
2. Open the filter - as if your intention is to clean the sponge.
3. Remove the sponge from the compartment.
4. Pull and remove the green flow control slider.This leaves a small opening on the side of the filter.
5. Close the filter without the sponge. When doing that put the CO2 tubing in the small opening mentioned above. Basically 1/2" of the CO2 tubing is now inside the filter, right under the intake, and it's held in place by the closed filter.
6. The filter comes with a flow nozzle. Put the sponge removed in step 3 over this nozzle.
7. Attach the flow nozzle to the filter.
8. Peel off the technical info sticker. It's white and attracts the eyes.
9. Done!

Basically you have done two things:
A. Put the CO2 tubing under the intake of the filter.
B. Attached the sponge on the outtake of the filter.

When the filter runs the CO2 bubbles hit the pump impeller and make a very gentle noise. This is your bubble counter. Count the bubbles with your eyes closed if you want. You will have to get about a foot from the reactor though - it's hard to hear if you are more than 2-3 ft. away.

When the bubles hit the impeller they get broken into tinier bubbles. These tiny bubbles then get trapped in the sponge with 60 gph of water flow disolving them almost 100%.

The few fine bubbles that escape the sponge look like a tiny cloud. It consists of bubbles so fine that they have a hard time floating up to the surface. Even the most gentle side flow carries them to the side and around the plant leaves.

Old design of mine but this $10 filter really makes it possible to make an ideal internal CO2 reactor in literally less than 1 minute. The filter is very small (easy to hide), black (doesn't attract the eyes), and has a strainer that makes the suction gentle enough so snails don't get stuck on the intake, die and block it. Virtually zero maintenance.

Maybe someone could post pictures showing how to do everything I described. I haven't picked up a camera in many months but it seems that life still goes on as usual.

--Nikolay
 
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#88 ·
I have never seen a ceramic disc diffuser produce as fine a mass of bubbles as this little one does, when it is working without too much CO2 being bubbled into it. CO2 mist works best with those very fine bubbles. Even those tiny bubbles don't disappear before reaching the water surface, but they float up much slower and linger stuck to the water surface longer. I don't think any CO2 bubbles actually disappear when they float up. Perhaps someone can explain that?? At one time it was said that CO2 bubbles trade CO2 for other gases in the water, so the bubbles aren't CO2 when they reach the surface.
 
#90 ·
Nice idea! Certainly cheap enough. Looks like a pretty fine mist.

I have had trouble with the ceramic diffusers seeming to clog, although not visible. I have had to switch out to a dry clean on and put the old one in bleach solution, scrub it with a brush, and treat with prime to get it ready for next switch out.
 
#91 ·
In that pic, the flow is actually set quite high, to give a clearer visual idea of what's going on. If I adjust the flow just right, I can acheive a very fine stream that barely even floats in the water, rather just drifts around low in the tank. As you can see, it's right below the filter outlet to help with distribution...
 
#92 ·
Ghengis,

If this is a chopstick from the nearest Chinese food place then congratulations! You may have joined the ranks of "cheap to the bone" hobyists :D.

Here's a "secret" trick; Cut the chopstick really short (1/4") and stuff it at the end of the CO2-tubing. Then stick that amazing creation under a powerhead. The CO2 fine CO2 bubbles will be broken to even finer bubbles by the impeller. Oh my!

A chopstick is nice but in a few weeks it will turn black from bacteria growing on it. Of course you can replace it, but the problem is that the CO2 flow will vary.

No chopstick, just the CO2 tubing in the powerhead inflow is a fool proof... exquisite... fashionable design. And cheaper than a free chopstick!

--Nikolay
 
#93 ·
Niko, close on the guess. It's actually about an inch of the pointy end of a bamboo skewer:cool:
Having tried various methods of separating the pointy bit from the rest of the skewer, from clean cutting to semi-cutting then breaking, I found that straight out breaking, leaving lot's of little fibres, to be the best as far as bubble-ation goes.
 
#94 ·
This little DIY reactor is excellent. I've been meaning to set DIY CO2 up on my planted tank for a long time, and uncertainty about a reactor was the only thing holding me back. I Found this article early this week, got everything set up, and I'm on day 3. I'm anxious to see some good plant growth. Thanks guys!
 
#97 ·
Blacklabel,

One of these reactors is perfectly fine in a 75 gallon tank. I suspect it can go up to at least 90. For a 125 I'd do a bigger powerhead with a sponge on the outflow. Also make sure that the bigger powerhead has a big size strainer. Usually powerheads have skinny strainers that suck not only debries but snails too. That forces you to clean them too often. A bigger size (diameter) strainer does not have such issues.

MooTycoonZaster,
This small reactor will be too much for a 10 gallon tank. But if you find a way to provide surface agitation a lot of the CO2 will get out of the water.

--Nikolay
 
#100 ·
ZooTycoonMaster,

If you run the CO2 on and off you will have big fluctuations of the amount of CO2 in the water. For whatever reason it takes much longer to saturate the tank with CO2 then to let the CO2 fizz out of the tank. It may take 2 hours to saturate and only 30 min. to loose it all.

Now, knowing the above doesn mean much. If the plants do well then by any means run the CO2 for only a short time every day. But the main question is how the algae are going to like the fluctuations of CO2. In general algae shows up when the tank is not being run consistently. If you start chaning the light, the water change schedule, the feeding, the ferts usually algae appears. So it would be logical to expect an algae bloom if the CO2 fluctuates up and down. Especially if you let the CO2 escape the tank and the lights are still on.

Maybe the most reasonable approach would be to run the CO2 when all your lights are on. And to reduce the light when the CO2 is off.

Or you can just buy a CO2 diffuser and make things simple :) A 10 gallon tank will look better with a tiny glass diffuser than with a black pump with a sponge on it.

Once again - if the plants grow and everything is fine run the CO2 any way you like.

--Nikolay
 
#102 ·
After having used this setup for a while, I find it works better if I don't put the tubing where the flow rate slider goes, and instead cut out ONE of the slats in the side of the inflow guard and stick the tubing there. The hole where the slider goes is just too small, and as a result the tubing was pinched shut after a while. No problems since I placed the CO2 line in the side of the inflow guard.
 
#104 ·
I did what Brendan Redler did without reading his post, for the same reason- the hole is just to small in the flow adjuster slot.

Anyways, this method seems to dissolve so much of the CO2, and the little bubbles leftover get swirled around my tank by my powerhead, so there is CO2 all over the place :D.

However, it isn't as quiet as it is made out to be for me. It sounds the same as what it did when I had my DIY going into my HOB filter. Same bubble crunching sound every time. I'll get used to it though- the price we pay for beautiful plants :D.
 
#106 ·
Saraja87,

For a 110 gals. tank try to set a rate of about 1 bubble per second. If things go well, no gasping fish and such then see if the plants like it. If the plants don't seem to perk up raise the bubble rate a little - about 1.5 bubbles per second (don't immediately go to 2 bps)

You will see tiny bubbles coming out of this miracle of a reactor. "Tiny" bubbles means they look more like dust and float up very slowly (cause they are too small and don't know what they are doing, you know).

It's hard to recommend a set bubble rate. If the tank handles it well - no gasping fish, plants doing well - then this is the bubble rate you should keep.

One thing to remember is to NOT let the surface of the water be without movement. The surface movement is extremely important for gas exchange. But too much movement will waste a lot of CO2.

--Nikolay
 
#107 ·
Help me understand something. If I am using DIY co2 method and I am using this filter as a diffuser and I want to only put co2 in to the water during the day, how can stop diffusing co2 into the water at night? If i run the pump diffuser on a timer and it is off at night, what will the co2 that is getting put into the pump intake do? will it escape and not go into the water or am I not going to be so fortunate? thanks guys!
 
#110 ·
Shutting off the pump at night works perfectly well. Big ol' CO2 bubbles make their way to the surface and don't solubilize in the water.

But my question is why would you want to shut off the CO2 at night. People that do that save a little CO2 from their pressurized setups, that's all. The plants don't benefit that much from lower CO2 at night.

--Nikolay
 
#111 ·
I haven't noticed much of a difference when I ran CO2 24hrs a day vs. when I ran it only with the lights. I have a solenoid valve on my pressurized setup and I think I'm going to take it off. It's needlessly drawing current because I have it running 24/7. I would say don't worry about it, and if you're still worried about it...you can either shut off the pump, or pull the CO2 line out of the bottle so that CO2 is just offgassing into the air from the bottle.
 
#115 ·
Stuckintexas,

I run all my CO2 tanks with the CO2 on 24/7. Never had a problem for 7 years now. Just the first night when I turn the CO2 I worry, but it's always in vain. No issues whatsoever.

--Nikolay
 
#117 ·
I think it depends on how hard you are driving your plants. If you try to run the maximum concentration of CO2 in the water, over 30 ppm, then the fish can be bothered by it at night, unless you maintain really good water circulation and make sure there is plenty of dissolved oxygen in the water - a little ripple on the surface helps. And, the smaller the fish, the less they seem to be bothered by the CO2.
 
#120 ·
This is one of the good things about this Elite filter thing - it has a big strainer that lets snails pass over it and not get sucked and stuck. I don't need to sacrifice my pantyhose, no sir!

Truly an amazing, miraculous, design!

--Nikolay
 
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