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Discussion Starter · #1 · (Edited)
We held the first ever South Florida Aquatic Plant Society meeting yesterday. I was extremely impressed by a member's ingenuity in creating a DIY CO2 bell for his nano.

Osteomata used a Tic-Tac container and siliconed it into the DIY yeast reactor line. The CO2 bubbles out and accumulates into the container. It them diffuses out slowly into the water column. I've attached a pic.

Well done Osteo!

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That's an interesting idea. I always enjoy seeing others' ingenuity at work.
Art or Osteomata, will you provide some comments as to the effectiveness of this bell diffusor (i.e. tank size, tank KH, tap wather pH, and level of pH maintained in tank when using this)?

Thanks for sharing the photo Art.:cool:

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This works for any size of tank. I use it for a 75 gallon tank (pH 6.6, KH 4). Here is a link to a German forum with some instructions on how to build it (you can use glass or plastic glas):


The second version is for labyrinth fish and should be placed near the water surface because of the ventilation. However, the amount of CO2 diffusing into the water does not depend on the height of the bell (1 to 1.5 inches is good) or how deep you place it in the water. It is determined by the surface area that is in contact with the CO2 under the bell.

The size (area) of the bell depends on your KH and the size of your tank:

For each 100 liters (25 gallons) of water:
kh: < 10 -> 30cm² (4.8 sq in)
11 -> 50cm² (8 sq in)
12 -> 70cm²
13 -> 90cm²
14 -> 110cm²
15 -> 130cm²
16 -> 150cm²

This keeps the CO2 level constant at about 20-30 ppm (depends on water movement below the bell).


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Well I can only provide a little bit of info about this DIY CO2 bell:

The tank is a 1 Gallon plastic hex, 8"L x 8"H x 5"D. The very limited size of the tank, plus my grandiose heavy planting left little room for a standard sized CO2 bell or even a hagen ladder. For a few weeks I just let the CO2 tube bubble straight out into the bottom of the tank. The Tic-Tac candy container struck me as an ideal choice for diffusing in this tank: very narrow profile. I used a hack saw to cut the bottom 1/4" off, drilled a hole and siliconed the tube in place. It was very easy to hide it behind the stem plants.

As for effectiveness:
Without CO2 addition, I have about 4 ppm, with the this diffuser closer to 20ppm.

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