Question about adding a second co2 reactor

[Xzap]

If I add a 2nd co2 reactor to my tank, will I need to use a gang vavle to send co2 directly to the 2nd reactor, which will be driven by one pump.

Thx,

Dave

 

[greenmaji]

If you are building a more effecient reactor.. you will likely only need it.. HTH
heck depending on how well the one you have is working you might not be better of with one.. but powered reactors seem to perform better..

 

[Xzap]

So the basic objective is to keep the co2 bubbles in contact with the water as long as possible, breaking then down into smaller and smaller bubbles. . and this would be considered 100% dissolution ?

I can't get my pH under 7.5 - 7.4 during the day and 7.2 at night. My KH is 4dkh, I've added a total of 1 tsp of baking soda this week in 3 equal doses.
po4 is 1.0
ates 10

Plants are growing good, but I'm getting fuzz and green spot algae.

Thx,

Dave

 

[afilter]

I suggest looking into a diffussion bell. Tetra use to make them. Then you get 100% gas diffusion. You could easily make one as well using a 20oz soda bottle:

1. cut off the neck

2. Poke a hole in the bottom

3. Insert a piece of rigid line through the hole about 1/2-2/3 into the open bottle leaving about 1/2" out the bottom.

4. Silicone the tube in place

5. Attach two suction cups to exterior of bottle.

6. Attach air line tubing to the rigid tubing coming out the bottom.

7. Invert bottle and place in tank suctioning to glass (let all Air out of bottle)

8. Periodically fill the chamber from your CO2 source. You could even leave it hooked up with a on/off valve just make sure you also have a one way check valve in place to avoid draining your tank.

It provides much better gas exchange than the bubble method.

Not sure what you are using for a CO2 source, but here is a cheap DIY method that worked for years for me.

http://members.aol.com/yamatoaquariums/co2.html

I used a clean 2 litter bottle and recharged it every 2-3 weeks. Once it is running a simple shake and you instantly have enough CO2 to fill your bells.

HTH,

 

[afilter]

Oh, the beauty with the bells is no need for multiple reactors. One reactor can fill them all. The tetra ones stacked so you could place them on top of one another and fill them in series.

 

[afilter]

I looked on the net and could not find the Tetra CO2 Bell. Tetra may be out of the CO2 business. I did find this pic which is similar to the DIY unit I decribed.

 

[Xzap]

All that sounds way too simple to be 100% efficient. What am I missing ?

I was thinking of using a large gravel vac tube (Thanks CZ) and force co2 and water into it from the top and let the water out thru the bottom, but force it thru a smaller outlet which would make it linger in the tube longer.

Basically if you turn a gravel vac tube up side down, you've got your built in small outlet with an anti syphon valve.

Dave

Edited: Oh this is good.. so these simple bell reactors are all you really need ?

DIY bell reactor

Here's another good article

 

[afilter]

Same principal and a vacuum tube would work. You might want to cut it done as most are a bit tall. You do not need that big of an opening though. Again if you seal off the top and thread some rigid airline tube in it which is used to fill the chamber with CO2. The CO2 bubbles up into the chamber displacing the water. Once it is filled turn off your valve or just disconnect the air line tubing and the CO2 will slowly diffuse into the water. Letting the CO2 continually feed will only result in large bubbles coming out the bottom for the chamber and wasted CO2.

As I recall I filled my chambers about once a day or ever other day when they had depleted down. It is very simple and very efficient. Several years ago when I built mine I could have spent $250 for a fancy CO2 system. Instead I opted for the DIY reactor and the Tetra bells at about $6-7 each.

 

[Xzap]

I'm thinking a long gravel vac tube would keep the co2 in contact with the water longer ?

Dave

 

[afilter]

The concern I would have is a lack of flow dispersing the CO2 throughout the tank. Would the column inside the tube become saturated and slow down the diffusion rate? Need to check with someone more familiar with Chemistry than I.

I just know the Tetra ones I used were only about 6 inches tall and even when hooked together they all still maintained contact with the water at 6 inches.

When I get home I will check to see if I still have one of the Tetra diffusion chambers and post a pic.

 

[Xzap]

Pix would be great afilter

What ratio is the size/number of bells to tank size ?

And my solenoid would shut the co2 off at the desired pH reading, correct ?

Thx,

Dave

 

[afilter]

I used 4 Tetra bells for a 75g. I did not get that technical with a solenoid. I simply filled my bells when they were empty with the DIY reactor I built. My plants thrived to the point that I was harvesting them and selling to LFS for several months before I moved.

 

[Zezmo]

I hooked my basic gravel vac style DIY CO2 reactor onto the outflow of my Canister filter. This last weekend, I hooked up my second Canister filter (Fluval 303) so that the outflow is blowing accross the bottom of the reactor. The intake for both filters is on the opposite side of the tank. I also set up a powerhead on the bottom behind some driftwood, with the jet pointed sort of diagonally accros the tank. This way I can be sure the CO2 is getting everywhere in the tank.

 

[Xzap]

I hooked my basic gravel vac style DIY CO2 reactor onto the outflow of my Canister filter.

How did you connect it, directly to the input tube, how far under the water ?

Dave

 

[Zezmo]

Yes, right on the end. The bottom is about 5" above my gravel. All my inlets/outlets, and the powerhead are at the bottom. The surface of my tank is very still. The Gourami's like it for thier bubble nests, and it keeps the CO2 in the water.
I basicly have one of these: http://www.barrreport.com/gallery/showimage.php?i=1&c=7 (link stolen from your other post ) attached to where the water comes back into the tank from my filter. That is instead of the powerhead shown in the picture. Mine is a simpler design than that one. No venturi loop, or burp hole, and I stuffed the open end of mine with some Eheim prefilter material ( http://www.bigalsonline.com/catalog/product.xml?product_id=24297;category_id=2627 )

 

[Xzap]

No kidding Zez.. That simple huh ?

So your input hose from your canister filter goes into the top of the vac tube along with co2, you point it towrds the bottom and fill the end with some filter media to make it dissolve better ?

What size gravel tube did you use.

 

[Zezmo]

I think it's about 2" in diamter. Here is basicly what I used:
http://www.qsl.net/w2wdx/aquaria/tube.gif

And here is what I based my design on:
http://www.qsl.net/w2wdx/aquaria/assemblyvsm.jpg
http://www.qsl.net/w2wdx/aquaria/explodedsm.jpg

In fact, it was this page here that I got a lot of my information from, as well as the sticky post at the top of this forum.
http://www.qsl.net/w2wdx/aquaria/diyco2.html#6

 

[Zezmo]

I am getting ready to do my weekly water change, so I went and tested my water.... curent Params are Ph=6.6 Kh=4deg (so by chart CO2 is 30ppm).

 

[czcz]

With powered reactors you're going for breaking the bubbles up instead of slowly letting them dissolve into the water column passively. This allows you to get high, consistent ppm, especially since youre running pressurized. Venturi loop design has an open bottom whereas the bioball design youre looking at forces bubbles to break on the bioballs; through either design you won't see many if any bubbles escape, just CO2 enriched water (though with venturi loop you won't want to inject CO2 at a rate where it constantly goes past the burb tube).

Assuming you can replace the line should you want to sell the canister later, you can use the entire return line as part of reactor by injecting right after the canister: I do this with my sump return and have the same numbers I did with a traditional powered reactor, so I believe either method dissolves all the CO2 my yeast based set-up produces. The effectively very long chamber forces bubbles to break up as its pushed along at a fast rate, but I only use DIY in relatively small volume, and a bioball chamber may be necessary with pressurized at your volume.

Zezmo's idea of feeding the gravel vac with the canister outtake makes sense to me too, but I dont think you should use use a line reducer to fit the gravel vac's end cap and I think you may need a couple bioballs in there to break up the gas to get complete diffusion with your setup.

I understand this may be a PITA, but once you get complete diffusion or close to it you're done, and your caves make me sure you can do this easily It's like 15 minutes tops for assembly, seriously.

HTH

 

[Zezmo]

I was lucky in that my Canister filter return line, and the inlet to my Gravel Vac Reactor are the same size. I agree that a couple bio balls would make it work even better. I don't have access to just 2 or 3...and don't want to buy a whole box for one or two. I figure I will come accross a couple at some point, and add them then.

On a side note, I considered of using the entire return line as my reactor, but I was concerned that the venturi action might cause too much suction on my DIY yeast set up.