Co2 System?

[CopperLeviathan]

Recenlty I saw a very interesting tank at one of our local Fish stores. The tank was a aquatic plant tank, and being the stores it had every bell and whistle. The tank also housed fish mainly Killies. I started to ask a bunch of questions about the tank because I wanted to have plants in my tank. I have a 20g and decided to buy a 75g tank to start off this project with. I want to take my time with this tank. I have been researching Co2 sytems. I have been in that fish stores and others asking questions. Most places don't have anything. The fish store does, but it is like they are talking in another language. I have asked about books, no one knows of any. I seen it mentioned in FAQ page, but no real help. What is need to have a nice Co2 system, where can I find more info. Anything would be nice. I just got bored of Plastic plants.

[phoenixshade]

I built my own CO2 injection system. It's actually very easy. All you need is an empty two liter soda bottle, about 5 feet of airline, an airstone, some silcone sealant (it need not be aquarium grade, as it does not ever touch the tank water), and a check valve. The only tools needed are a drill with a 1/4" bit and an exacto knife. Optional: Low wattage heating cable.

Remove the plastic doohickey from inside the bottlecap. Cut out the center (using an exacto knife), leaving the outer rim untouched. Do not discard this thing, as it is what forms an airtight seal when the cap is on.

Put the bottlecap in a vice. Using a 1/4" drill bit, drill a hole through the center. (If you don't have a vice, you can carefully hold the bottlecap with a pair of plyers while you drill.)

Run the airline through the hole so that about 1 inch is on the inside of the bottlecap. Use silicone on both the inside and outside of the bottlecap to make an airtight seal. Allow to set overnight.

Replace the aforementioned plastic doohickey inside the bottlecap. Cut the airline about one foot from where it exits the cap and insert the check valve so that flow can only go OUT of the bottle and IN to the tank.

Note: This check valve is very important, as I learned the hard way when my A/C first came on this summer and created a siphon by sucking tank water down into the bottle. The tank didn't drain, but the water was contaminated with yeast!! (It didn't seem to hurt the fish, but it sure smelled bad!)

Attach the airline to the airstone. Place the airstone in the tank, inside of an inverted plant pot or boiled coconut shell half, so that bubbles that it emits are trapped.

Fill the bottle about 1/4 with lukewarm (not hot) water. Add one packet of dry active yeast and 1 tablespoon of sugar. Swirl mixture until sugar dissolves. Put the cap on the bottle. About 10 minutes later you should see bubbles forming on the airstone. This is CO2!

For optimum performance, wrap a low-wattage heating cable around the bottom 3" of the two liter bottle. Attach with duct tape. Put this on a timer that turns on with the lights and turns off about 1 hour before lights out.

Dump and replace the yeast mixture about once per week. In a 75 gallon tank you may want to make two of these. Change the mixture in one on weekends and in the other in the middle of the week.

Besides CO2, your plants will need a good source of iron and potassium. Use a 1" base layer of a laterite/fluorite mixture for your substrate, then put down 1" of gravel, mix well, and top it off with 2 or 3 more inches of gravel. Do not use an undergravel filter, as aeration around the roots slows or stops nutrient uptake.

May your thumb grow ever greener!

- Wil

[CopperLeviathan]

Thanks Phoenixshade.
Looks like I'm going to have to start a little project when I get done moving. I do have one question about the yeast, is that normal bread yeast or beer yeast?

[phoenixshade]

Well, all yeast produces CO2; I use normal bread yeast... Fleischmann's Active Dry Yeast, to be exact, which comes in 1/4 oz. envelopes just perfect for one week's use. I guess beer yeast could work, too.