DIY C02 attempt - some questions, diagram, links

[PintoHawk]

These are the instructions/suggestions I am following:
http://www.tropicalfishcentre.co.uk/Diyco2.htm

3/4 of the way down this page, the diffusors:
http://www.thekrib.com/Plants/CO2/

Here is my fantastic, professional-looking hand-drawn diagram of the c02 I wish to make. Bear with me. Not to scale, haha.

http://i414.photobucket.com/albums/pp228/thefishfiles/diy/plan1.gif

Ok, so my questions are...

Valves - necessary for safety and control of flow... how do I attach it, and where?
Bell Diffusor - will it be heavy enough on its on, or do I weigh it down to the bottom somehow?
Airstones - better than a Bell?
Filter - I read you can use the filter to push the C02 bubbles into the aquarium, but where exactly do I put the tubing so it will do this, and not back up the bottle? I have hang-on-back filters and one tank has a sponge filter currently.
Bottle sizes - I have a couple 10 gallon tanks I wish to use C02 on, can I use a smaller bottle?

Any other suggestions/comments? THanks! :D

[thegrandpoohbah]

No valves: you can't shut off or restrict the flow without the risk of your bottle exploding.

Bell diffuser: Depends on what you make it out of but it will likely float (it's filled with gas).

Air stones: no, a bell diffuser should work better. You want to prolong contact time of the bubble with the water.

Filter: You would run the CO2 tubing into the intake of a submersible filter. This one works well for this application: http://www.hagen.com/canada/english/aquatic/product.cfm?CAT=1&SUBCAT=107&PROD_ID=01001300011001

Bottle size: the bigger the better. You will be able to go longer between re-fills.

[sass]

My DIY co2 system has a check valve, I think that's what they are called, situated in the tubing between the yeast bottle and the diffuser?
Keeps the tank water from siphoning back?
My bottles sit below the tank hidden in the stand.
Cheers

[PPulcher]

A check valve doesn't add too much back pressure to the system, and I would advise one to stop siphoning as has been mentioned. I've read that some people have mixed a new batch of yeast/sugar water and it was a little bit warm and a little bit full in the soda bottle, only to have the bottle cool and draw water into the bottle. Once the fermentation happens, the yeast/sugar water is expelled into the tank, creating a big mess.

In terms of making the cap for the bottle: I've had much better luck using a very flexible type of tubing (like silicone). Drill a hole in the cap a little bit smaller than the outside diameter of the tubing. Crush the tubing a bit and pull it through - it should expand to close the gap pretty much air tight. I've never had luck with silicon sticking to the plastic cap. A bead of hot glue has worked much better for me.

[thegrandpoohbah]

Sorry. Check valves are indeed a good thing. What I meant was that a valve to restrict or control the flow out of the bottle was bad.

[OldMan]

I have seen lots of suggestions to use a bubble counter on a DIY CO2. There is no way to adjust the bubble rate but another function of a bottle between the yeast bottle and the tank is to catch small overflows. Otherwise, you should leave more head room in the soda bottle to make sure nothing but the gasses ever go into the tank. On many forums, where people are DIY CO enthusiasts, there are frequent posts about the yeast mix getting into the tank because someone pushed their system with too high a water level in the bottle.

[Namor]

I have no experience with CO2 (as of yet), just wanted to say nice work on that diagram.:yes:

[PintoHawk]

LOL, thanks Namor. :)

Thanks, everyone, for your input. Hmmm...

So, I went with the airstones. I glued the lids/tubing yesterday, and washed the bottles out. This afternoon, I will set one up and see how it goes. *crosses fingers*

I will take your advice, Oldman, about not overfilling the bottle (I was considering that), especially in these trial stages where I will be too nervous to leave it alone, haha.

[sass]

Not sure what type of yeast you went with but I use champagne yeast rather than the regular brewers yeast.
I was told it produces better and for longer:Dunno: .
I have problems with my DIY co2 system in the winter due to the house cooling down so much and the bottles getting chilled.

[PintoHawk]

So, I set 2 of them up on 2 different tanks, it has been a few days, and still nothing. I figure it's because I was nervous about filling the bottles up too much (explosion of yeasty syrup = not good), and I should've filled them more. Maybe I will add more ingredients today and see how that goes. *chewsfingernails*

[PPulcher]

In my experience, the airline to cap connection is almost always to blame when no bubbles appear. It's the toughest part of the rig to get sealed properly.

[PintoHawk]

Hmmm...

Perhaps I should add some more silicone to the airline/cap areas, then, and try to seal it off better. I thought I had used excess amounts to be certain, but I can do some more, I suppose. It's worth a try.


Also, I had attached valves to the tubing, between the cap and the airstone, closer to the cap of course, so I can access it outside the tank. I am thinking there might be leakage happening in there, and I want to remove the valves, but how can I get the tubing back in one piece? Electrician's tape? Duct tape? Will either of those be airtight?

[thegrandpoohbah]

Also, I had attached valves to the tubing, between the cap and the airstone, closer to the cap of course, so I can access it outside the tank. I am thinking there might be leakage happening in there, and I want to remove the valves, but how can I get the tubing back in one piece? Electrician's tape? Duct tape? Will either of those be airtight?

Just get new tubing. You won't be able to seal the two ends back together very well. What kind of valve is it? If it's just a standard check valve then I doubt that is the source of your leak.

[Blossom112]

Thanks for posting .... think I will try one myself!!!
I have everything I need somewhere around here .
I have time now to experiment!

[mdfa.ca]

In my experience, the airline to cap connection is almost always to blame when no bubbles appear. It's the toughest part of the rig to get sealed properly.
Trust me, if the yeast looks like it's reacting in the bottle itself, this is indeed the source of the problem. THis connection has given me troubles for weeks and just about made me stop doing CO2 all together. I tried hot glue, regular glue, bead glue (don't laugh!) aquarium silicone, everything leaked. Until I did what Oldman suggested to me a while ago (thanks, Oldman!:notworthy:). Drill a small hole in the cap, much smaller than the tubing itself. Cut tubing at a sharp angle, squish it and push a bit through the hole. Grab it with small pliers gently from the other side and wiggle/pull until it comes through. It will get squeezed and get smaller, but there is enough room for the gas to get through. The beauty of this system is, the higher the pressure of CO2, the tighter the seal. All 4 of my systems are set up like that now and I have had no leaks.

The overflow bottle - it is a really good idea! Even if you leave a lot of room at the top of the bottle, some yeast may get through. That's what just happened to me. The overflow bottle also acts as an excellent bubble counter because you can see the bubbles coming out.

Diffusion - There are many ways. The simple the better. I can only tell you what I use and how it works for me: In one of my 20 Gal I have the plastic "ladder" thingy. Pretty happy with that, except that it's a pain because it eventually does get dirty and accumulates some algea, and it's hard to clean with all the differently angled sides etc... I also positioned one of my AC filters' intake in that tank right over the exit so it does catch an occasional bubble aiding the dispersion.

In my 5 Gal at work, I just use a small, regular airstone. Works just fine. IN my 10 Gal I also use an airstone, but have it positioned under a tiny powerhead which I pulled out of a toy fountain. The thing is about 1" cubed. It sucks in the bubbles and throws them into the water all tiny and chopped up. It would work the same if you stuck it under any filter intake really.

The other 20 Gal is an interesting experiment. I only use a regular air stone and have it attached to the wall at the bottom using a suction cup. But, I have a fine leafed plant (water sprite) growing all around it. The bubbles go up, get trapped by the fine leaves and sit there until they dissolve. The CO2 saturation in that tank is the same as in the other 20 Gal - optimal, as in, the indicator is light green. You should see the jungle in that one!

I would really recommend getting a CO2 indicator, one of those that you stick on the glass in the water. They go for about $16.00 and are really handy. Give you a quick idea of what is going on with your CO2 without having to sit and count bubbles LOL.

Sorry for getting so wordy. If you have any questions, just ask. And I can also post photos of my setups if you'd like. Just let me know.

Margaret.

[mdfa.ca]

Just get new tubing. You won't be able to seal the two ends back together very well. What kind of valve is it? If it's just a standard check valve then I doubt that is the source of your leak.
You can also got plastic connectors in the LFS. cheap. I have never found them to leak.

[Blossom112]

can you just add the tube from the bottle to the powerhead ?
and how low do you put tubing in bottle ?
and how do you do an overflow bottle ? you have a picture ?
I am just trying to make my cap now lol

dont mean to hyjack .. just a few questions

[mdfa.ca]

Hi Blossom,

In the yeast bottle the tubing only goes about an inch from the cap. You don't want it anywhere near the yeast mixture. For the overflow bottle I use a 355 mL Tropicana juice bottle. It's smaller (you don't need large here) and it has a wider lid. Fill it only about 2/3 with water. Make two holes (one for line going in from the yeast bottle, the other for the line going out to the tank. Again, the tubes only go in about 1" into the overflow bottle, but the the one that came in from the yeast I attach a piece of hard tubing long enough so it goes below the level of the water.

If you give me a couple of hours I'll take a picture of my system here at work.

Margaret.

[mdfa.ca]

Here is what I have at work:

http://i37.photobucket.com/albums/e62/mdfa/DIYCO2setup.jpg

home setup is basically the same except that I use a rigid line in the overflow bottle. The soft ones tend to curl over time.

Margaret.

[Blossom112]

I cant tell you how much the pictures have helped me .
Thank you so very much!!!

[nathan u]

big thing to watch with those plastic connectors and check valves is that they don't melt open/shut.

apparently that is a possible issue with the co2 so a metal/glass check valve might be a worthy investment for the hardcore diy co2 enthusiast/compressed canister.