Here's a small little highly effective DIY Reactor that cost about 11$ with the powerhead, or about 2-3$ without.

Materials:
12" rigid airline tubing 3/16" OD
4" L x 2" OD Viewtainer
Lighter
Snips or shape knife
Metal rod/small screwdriver, about 1/8" or 3/16" diameter

Procedure:

1.The bottom removal part of the viewtainer is discarded.

2.A small slice is made in the top of rubber cap to wedge the elbow that comes with the Rio powerhead 180, see inside picture. The direction should provide a spiraling downward direction of flow, no sponge cap at the bottom is needed.

3. Be careful to make the slice small enough to get a good seal for the
powerhead. This is the hardest part of making this reactor.

4. Take the lighter and heat the small rod or screwdriver up. The diamater should be slightly smaller than the standard 3/16" rigid tubing used for aquarium aeration.

5. Melt the two holes on the side of the reactor tube

6. The burp hole should be able 2.25" down from the top of the reactor.

7. The venturi loop should be about 1.75-2" down from the top of ther reactor. This hole should be on the same side as the filter basket, the burp hole should be on the opposite side.

8. Insert 1" rigid tubing to both holes.

9. cut a 5" piece of rigid tubing, make a slight bend 1" from the tip, this will help cebtor the CO2 bubbles up the middle of the reactor and prevent the bubbles from being blown out.

10. Make small notch so that the seal is air tight and snug next to powerhead and insert the 5" piece of rigid tubing through the top rubber lid(this is where the CO2 gas is added, it also acts as a bubble counter).

11.Roate tube's bend until it's centered

12. drill or melt small 3/16" hole into the powerhead intake basket so that a 1" piece of rigid airline tubing is snug.

13. Connect with silicone air line the venturi and the filter basket. This will make the venturi loop and degas the build up thatb occurs after a few hours and produce a mist effect.

14: Melt proper size suction cup hole with lighter, insert suction cup

15. Add CO2 line to 5" rigid airline tubing

Place in tank, plug into the light timer and you are done!

Time: about 15 minutes once you have the parts.
Viewtainers can be found on line, at Home Dept, Orchard Supply and Hardware etc.

Hints:

1. You can take the tips of the rigid tubing after it's inserted or prior and slightly heat and the tip should swell, this will prevent the tubing from being pulled out later.

2. I tyically add the rio 90 degree elbow through the rubber cap first, then snap on the powerhead after the tip is pushed through the rubber cap.

I have been trying to clean out all of the algae I can find in my tank, an almost impossible job. One problem is that algae is growing inside the viewtainer part of my venturi reactor, and it's construction is so flimsy that I can't do an effective job cleaning it out. So, I made another one, with some changes. First, I discovered the secret to finding viewtainers in the stores. Orchard Supply Hardware keeps them in the tools section, where it is very easy to overlook them, but after searching the entire store I found them. Only $2 for a 2" diameter by 6" long version.

So, here is what I ended up with:




This one is made from my Maxijet 600 powerhead. I have the outlet going into the side of the top of the viewtainer instead of down thru the top to an elbow. It is a bit off center on purpose. The purpose is so I can use the existing suction cups on the powerhead to mount it making it much more securely mounted. Next, I have the CO2 inlet coming in thru the side of the viewtainer instead of thru a long tube down from the top. This makes it easier to brush out the inside. Finally, I have a coarse sponge on the inlet to the powerhead to keep baby shrimp, etc out. Tomorrow I will see how well it works.

Edit: It works just fine. Smaller CO2 bubbles coming in, since they go thru a little airline connector, and it starts producing a little CO2 mist almost as soon as it starts up. It quickly builds up the CO2 to around 40 ppm with no problems at all.

Tom,

I noticed the other night when the reactor was turned off (and the lights as well) that the CO2 buildup was bubbling every so often, like 5 minutes or so. I thought nothing of it, because that is what the burp hole was designed for.

Well, I decided to watch it just for curiosity's sake, and it turns out that it doesn't even build up close to the burp hole. Instead, it is burping out of the powerhead intake! What do you think of that?

Here is a pic of it, although it has moved to the outsource of the filter now:


Current placement:

That's fine, the only issue is potentially locking the impeller with the gas, but that's why it's mounted vertically and should pose no issue.

The burp hole allows for volume specific volume before leaking out, say if you added too much gas for the venturi can handle.

This prevents the entire tube from filling up and knocking off the suction cup and having the entire reactor come loose.

You can add several such burp holes in the side of any such reactor, then use those air line plugs to add or remove the holes to get the desired level or effect.


Regards,
Tom Barr

That makes sense. The burp hole works while the reactor is on. Guess I should have put a little more effort into the thinking process first. I hate getting older.



Thanks,

Since your tank is long, you might consider placing near the filter in take end, and blast the water without the spray bar, just the open tubing, all the way towards that side.

This will mix the CO2 throughout the tank well.
Either that, or adjust the water flow so that the filter blast near the diffuser and then down the length of the tank.

Regards,
Tom Barr

Hey Tom,

What size power head do you recommend for this reactor?

I assume that there's an optimum size that will provide good mixing to dissolve CO2 and shoot out the small bubbles without ejecting large bubbles and wasting CO2.

Also, did you try other diameter reactor tubes or just this one because it was easy to find and worked well?

Thanks!

I tried a few other sizes, but they get too big or so small that they do not work well..
I use a rio 180 powerhead typically.

Regards,
Tom Barr

Cool. Do you happen to know the flowrate at 0 head for that model? I was flipping through the That Fish Place catalog last night and the rio's they offered started at the 400 series model which would probably be too strong based on your comments...

EDIT > Never mind, I found it at D&T Aquarium Supplies for $9. Pumps 120 gpm at 0 head and 85 gph at 1 ft of head.

Hey,

can you recommend something as a replacement for the viewtainer as i cannot seem to find them in Canada, specifically Toronto.

Thanks