Tropical Fish Forum
Tropical Fish Keeping Help and Advice => Fish Tanks and Equipment => Topic started by: ColinB on June 09, 2016, 08:21:47 AM
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Yesterday afternoon I made myself a CO2 generator from a fizzy drinks bottle and some left-over air line bits'n'pieces.
Dry stuff: Drill a 5mm hole in the bottle top. Slice the end of the air-line into a point and, using pliers, drag the air-line a few cm through the bottle top. This gives a good enough seal for the meagre amount of pressure generated. Shove the other end of the air-line on to an unused air stone.
Wet stuff: Dissolve 1½ cups of sugar in a jug of water. Add the water to the bottle and top up to about ½ full (or ½ empty if you're feeling pessimistic). Shake well. Add 1½ tsp of fast-acting dry bread yeast and shake well.
Stand the bottle somewhere suitable, put the air-stone somewhere suitable..... and wait.
Remember; the CO2 has to displace all the air in the bottle before it gets in to the water, so it will take a while.
IMPORTANT BIT: There is absolutely no control over the amount of CO2 generated this way and it is entirely possible that it may cause a pH crash in your tank. You do need to be well up on the relationship between pH and KH and how this affects the CO2 content of your water, and have test kits for both pH and KH. Dissolved CO2 chart here (http://www.thinkfish.co.uk/calculators/phco2).
I'd only got a short bit of air-line so this isn't the final resting place if I decide to keep it. However; as this is the hardware section of the forum I'll discuss the efficaciousness (or otherwise) of the CO2 addition elsewhere.
If the bottle is below the tank then an in-line non-return valve would be a good idea.
DISCLAIMER: I am no way responsible for the sticky mess that may ensue from any attempt to recreate the above contraption.
And, before you ask.......
(https://lh3.googleusercontent.com/-cduFPxaUp0E/V1kUlRtT8nI/AAAAAAAAFYo/KOkPU9e1rO8DYyGHeD5q7h2zpwD6e9ZFgCCo/s512/DIY%2BCO2.jpg)
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For anyone wanting to try this, Allinsons make tubs of dried yeast which are much more cost effective than those cardboard boxes with sachets of yeast. They actually make 2 - a green one for breadmakers and a yellow one for making bread the proper way, I'm not sure which would be best for CO2 generators. Once opened, keep in the freezer.
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I use the green tub. You have to 're-activate' the yellow tub yeast. As I make a lot of bread then the green tub can be kept in the fridge as I get through it quickly enough before it goes stale.
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I assume at some point you'd have to either top up with sugar or add more yeast?
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I assume at some point you'd have to either top up with sugar or add more yeast?
Yep! Although I'll probably just get another bottle started and swap them over.
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I use the green tub. You have to 're-activate' the yellow tub yeast. As I make a lot of bread then the green tub can be kept in the fridge as I get through it quickly enough before it goes stale.
I only make one loaf a week, just for me as my husband reckons home made bread has too much flavour which drowns the flavour of whatever is in the sandwich :o So one tub of yeast last me quite a while, which is why I keep it in the freezer.
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....my husband reckons home made bread has too much flavour which drowns the flavour of whatever is in the sandwich....
(http://vignette4.wikia.nocookie.net/disney/images/c/c6/Alice-facepalm.jpg/revision/latest?cb=20140910040316)
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Exactly ;D