Trying CO2 advice please

[Fishnut]

Ok...I decided to give it a try.  I have been determined to keep things simple with my tanks and keep plants that don't need a lot of extra lights or the addition of CO2.  So far so good!  I really like my tanks.

I caught the moss bug and I'm putting together a 20 gallon tank with the mosses I collect and I want to try CO2 in that tank to help my moss.

So far, here is what I have:

1 plastic bottle
airline tubing
sugar
yeast

Do I have to silicone the hose to the bottle cap or is there a less permanent/smelly solution?
How much sugar and how much yeast?


Where can I get one of those little racks for the bubbles to flow along...or better yet, where should the end of the hose be put in the tank?

If I have as much success with it as others here have had, I MIGHT put one on my 72 bowfront.  I'm worried because I'm at my max # of fish (see my signature) and I don't want my fish to swim around gasping due to the addition of CO2.  What advice do you have?

[Zoe]

http://www.fishforums.com/forum/aquatic-plants/16812-diy-co2-reactor.html

Don't silicone the tube/cap - as shown in the DIY pics in the link above, drill a smaller hole to create a tight seal.

But the end of the tube as long in your tank as you can... and if you put it in the way of water current, even better. You can the bubbles to spend as much time in the water as possible before they hit the surface. If they disolve before breaking the surface, you've done your just perfectly.

You can the ladder / CO2 diffusers from ebay.  BA sells them but a high price.

Use about 1 cup sugar to 1/2 tsp yeast.  I think - check the thread as I can't remember

I would not suggest DIY CO2 on a 72g unless you have very low light - and even then, you will need 2 to 4 reactors. Best to go with pressurized in that size - no mess, no hassle.

DIY CO2 does not inject enough CO2 to possible harm your fish.  You can keep a balance by having some water movement (I'm walking more about small waves caused by an HOB, than an airstone, which you don't want).  You want to make sure there is a balance - enough CO2 for your plants and enough O2 for your fish. It's hard to kill your fish with DIY CO2, though. You might succede if you plunk a fish right into the sugar/yeast/water mixture, but other than that, no

[Zoe]

http://www.fishforums.com/forum/aquatic-plants/16811-co2-discussions.html
For good measure. Sorry these all link to another forum

[washefuzzy]

Thanks for this great info Zoe.

[Fishnut]

That was a great DIY post!  Thanks.

[charlie]

Here is another  article , same princaple as Zoe.
http://www.qsl.net/w2wdx/aquaria/diyco2.html

[nanogal]

If you want more C02, why not just have multiple generators as recommended by Charlie?  I have a 2 litre pop bottle for my 5 gal, with inefficient diffusion by airstone, but because the 2 litre bottle produces tons of C02 compared to the volume of the tank, it works great.  If I had a bigger tank, I'd probably just attach several bottles to eachother via airline tubing to collect more C02, but of course, that's because I can't yet invest in pressurized...
I have the bubble stream right beneath the current from the filter output, so my C02 level is about 20 ppm with a simple airstone. 
Out of curiosity, why not silicone the tube to the cap?  That's what I did...  Should I not have?

[Toss]

The material in silicone and the bottle cap do not bond very well. Over time it will leak.

[nanogal]

Very good to know! 
At least it's really no problem to replace it when it happens
2 L pop bottles are free, and I have way more tubing than I needed for my first set-up.

[dan2x38]

I follow the set-up from Charlie's post. It works perfectly. I use the bulkhead fittings because it is hard to attach the tubing to the bottle caps. There is a glue for gluing polyethylene. You do not always know there is a leak after all it is a gas. Adding to much light and not enough CO2 is a recipe for an algae bloom.

I keep my CO2 levels fairly constant by starting the generator with only the one bottle mixed. The other bottle is filled with just plain water. One week later I make the 2nd mixture. This way every 7 days the level is being boasted for me this cycle maintains a constant level. I stick a piece of tape with the date on each bottle each one is changed every 14 days.

Diffusing the CO2 is the real trick. By the time you have your system tweaked and the mixture down pat it will be to no avail if the CO2 is just gassing off from the surface. So without a good seal on the bottles when you start using certain methods to diffuse the back pressure will blow the seal and loss all the CO2 or part of. For that reason I use the small bulkhead fittings shown in the article posted by Charlie. And it is easier to service. I've tried attaching the airline other ways and by sticking the bottles in a bucket filled with water gas was escaping.

[BigDaddy]

DIY CO2 does not inject enough CO2 to possible harm your fish.  You can keep a balance by having some water movement (I'm walking more about small waves caused by an HOB, than an airstone, which you don't want).  You want to make sure there is a balance - enough CO2 for your plants and enough O2 for your fish. It's hard to kill your fish with DIY CO2, though. You might succeed if you plunk a fish right into the sugar/yeast/water mixture, but other than that, no

Actually that isn't entirely correct.  With DIY CO2, the point is to raise the CO2 levels as high as possible before lights on (when nothing is consuming the CO2 so the levels can build) so that you have your target concentration at lights on.  When the lights come on, in a healthy tank the CO2 should dip until you hit close to your minimum concentration by lights out.

Problem is, when you are playing with your mixes, it can be very easy to have too high a concentration the following morning.  I know... I've done it. 

Yes it is "harder" to kill your fish with DIY CO2, but it is certainly not that hard when you are first playing with your recipe and doing the tweaks necessary to get the most bang for your buck