Grrrr C02 - How simply can I do it??????

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julicat

Aquarium Advice Regular
Joined
May 23, 2004
Messages
70
Location
San Francisco, CA
Bear with me please.

Due to algae problems and plants not doing as well as I hope, I've begun seriously flirting with starting a do-it-myself C02 thingy...

I read this and that and concluded: I get a 1.5 or 2 liter bottle, put airline about an inch into the bottle lid and seal it on both sides with silicone. Next, put the correct mixture of elements (yeast, sugar, etc.) into the bottle. Seal the bottle. Put an airstone on the other end of the tube and shove it into the tank somewheres. Change the mixture every week or three, Voila. C02 production. There was much rejoicing, etc.

More reading led me to decide it would be good to put a one-way valve somewhere on the line between the C02 bottle and the tank. Okay. Accepted.

NOW I'm reading about how the C02 gas collects, how it's dispersed...

My head's startin' to hurt.

Can I just put the C02-producing airstone in the tank...or, perhaps to better effect, in the HOB filter resevoir? Do I need to assemble more thingies and processes to truly achieve a viable C02 system? Have I basically only half-researched this and half-thought this through?

Right now I have a few boxes of C&H, unopened packets of yeast, a bottle cap with airline sealed into it (hanging out of reach of Leon, the gray cat), some capless 2 liter bottle kickin' around somewhere, and good intentions and limited energy.

I fully accept that I am lazy and not the brightest glolite in the school.

Thank you in advance for any avocational support given.

Your humble julicat
 
I know you already sealed the tube, but IME the seal works a lot better if you use rigid tubing. Cut a 2” piece of rigid plastic tubing. Drill a hole the same size as the rigid tubing. Force the rigid tubing into the cap. Make sure you leave the original plastic seal on the cap, do not remove it. Put a bead of silicone sealant on each side, and it will be leak-free.

As far as injecting the bubbles into the tank, what you are looking for is a diffuser. A google search on “CO2 diffuser” will yield many DIY options, but IMO it’s far easier to just buy a diffuser, like this.

All you would need is the $10 diffuser.

For the recipe, I used 6 cups of water, 2 cups of sugar, 2 tsp of yeast, and 2 tsp of baking soda. I also had an undrilled cap available to make the shaking easier. I started by putting 2 cups of HOT tap water in the bottle (hot water right out of the tap should be hot enough), adding the sugar, and shaking the bottle until the sugar dissolves—about 30 seconds. I then added 2 cups of COLD tap water, put the yeast in the bottle, and shook for about 10 seconds. Then I added 2 more cups of cold water, added the baking soda, and gave it a final shake.

I actually had two bottles set up and would change one every week. This way the CO2 injection is leveled out and there is less of a pH fluctuation.
 
I know your head is hurting, but one quick question: Do you know the kH(carbonate hardness) of your water?
And another: What size tank are we talking about here?
And a couple more: How many plants? How much light on top?
In order to give a somewhat informed response these should be known.

Len
 
20 gal tank

A few 3/4 year old spires of (i think) Ammannia senegalensis
1 microsword
Numerous arcs of either Hydrocotyle leucocephala OR Houttuynia cordata OR some like plant
2 spade leaf plants

Never measured Kh (don't have measurement kit for it)

Coralife 50/50 28 watt
 
Your algae problems are more than likely related to your light. A 50/50 light is normally used for a reef setup and the actinic side of the light doesn't do a whole lot for plants but can lead to algae.
 
A Coralife 65 watt light with 6700k lamp would certainly help, or better yet, an AH Supply 55 watt which is 60% brighter than standard PC fixtures like Coralife's. Do get a KH test (Aquarium Pharm.) .

You can use the airstone under the gravel DIY CO2 plan as you have stated just fine. HTH, BOB
 
Hmm, fish store people won't tell ya nuthin.

I will cast about for light articles...but (remember: lazy, not bright) what would be the best Coralite light for fw with plants?

And my big question: if I shove an airstone on the tube coming directly from the C02 bottle and shove the tube in the tank gravel, will the C02 work its magic? Is part of this C02 process that the gas has to collect and amass somewhere in the tank or something?

Thanks for all this input, everyone.
 
The gas won't diffuse very efficiently from the bubbles as they leave the airstone and float to the top of the tank, where it's lost into the environment. A large surface area helps the diffusion, so you want to:

a. run the airline from your DIY co2 bottle into the intake of your power filter. The impeller will chop the bubbles up and mix them with water, but it may be loud.

b. take a small glass, put it in your tank, and flip it upside down. prop it up on a few rocks, so that water can easily flow past the open, downward facing end of the glass. Run your Co2 line so that the bubbles from it collect in the cup.

Neither of these will look pretty, but they'll work. You can make them as fancy as you want, or as simple. Or you could just shell out $10 and buy one.

Good luck!

-J
 
http://www.plantedtank.net/co2reactor.html

i never tried this method, but it seems very efficent and easy. The power head blows air into the tube where the CO2 lies. There it is trapped with a sponge and diffused into the water.

I've tried a 3L bottle DIY CO2 and it lasts me more than a month

water 2 inches from the cap
3.5 sugar
1tsp yeast
1tsp baking soda

it starts working in 2-3 days but it seems fine. I attach a airstone into it and i use no seal because the hole i drilled was tight enough for air not to go through
 
O.K. Lets keep it simple Julicat. Do the whole DIY 2 liter and pop the $5.00 bucks or so for a Hagen ladder which you will run your hose to from the 2 liter. The ladder suction cups onto the glass and you can hide it behind rocks or a plant. It will work just great on a twenty. That is what I have used in my 18 gallon with a 36 watt AH Supply light. Moderate light plants grow great with this setup.

I would get a 36 watt or the 55 watt from AH Supply over anything Coralife sells. The replacement bulbs are half the price at $18.00 once a year. They sell enclosures if you don't wanna make one. Or just get a single 65 watt coralife online from Big Als or Drs. Foster and Smiths with the 6700k lamps (they come standard with that fixture (if its marked for fresh water planted). Then all the pieces should fall together nicely. :) HTH. BOb
 
thank you thank you thank you all

kwikky: the end of the airline in the C02 bottle should be OUTSIDE of the water/yeast/etc mixture, not immersed in it, right?
 
the end of the airline in the C02 bottle should be OUTSIDE of the water/yeast/etc mixture, not immersed in it, right?

Correct--as a matter of fact this is essential. It will force that stuff right down the airline and into your tank if you are not careful. If your airline tube is about an inch into the cap, and you use 6 cups of water, you'll be fine.
 
Thanks for info all.

The C02 thingy is bubbling away into the tank. The C02 airstone is just affixed to the front of the tank for now so I can see that it's working. It's working. Seems to be working great, actually. Very productive mixture apparently.

Is it possible or common for the water to take on a very slight milky hue when C02ing? It might be my imagination...

Is it possible for fish to OD on C02 suddenly coming in?

Anything I should worry about? I love to worry...
 
An air stone is not the best way to deliver DIY CO2. They can clog from fermentation by-products and cause the bottle to burst. Also you should build a gas separator to go between your generator and the tank. If the tank is milky it's very possible that some of the mix has gotten into the water. Do several large water changes NOW!
 
Is it possible or common for the water to take on a very slight milky hue when C02ing? It might be my imagination...

Agreed with rex, if you have a milky hue you need to do immediate water changes.

Is it possible for fish to OD on C02 suddenly coming in?

Yes, but this is mostly a concern with those that use bottled CO2, not a yeast DIY solution. Your only concern is the pH. Like it was said before, you need to get a KH tester to see what the KH level is, and then go from there. Once you get that and measure, I can give you a website that lets you easily tell the concentration of CO2 in your tank.
 
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