This was meant to be a temporary replacement CO2 until I have my pressurised CO2 kit repaired (broken valve). Used this in total for about 4 weeks. For the price- it surprisingly felt solid.



Used this for the citric acid and bicarbonate method- so can't comment on the yeast/sugar fermentation method. There are a few videos out there showing how it's done. In my experience;



1) You are going to waste a couple of reagents until you get the feel of it- always buy extra. I got mine from Wilco- cleaned the entire shelf of citric acid (£1.50 for 250g) and bicarbonate (£1.50 for 500g). You will also need 2 x 2L bottles, a check valve, a drop counter, a diffuser, and a drop checker (if you are going into the CO2 world- I'm sure you know where all of these should fit).

2) The instructions on Amazon is 200g of citric acid to 600 mls of water into Bottle A- and 200g of sodium bicarbonate to 800 mL into Bottle B. I note the Chinese instruction booklet that came along with it said 200g into 200 mL for both. Tried this- disaster (will explain later).

3) Close the valve in B.

4) Initially, when you squeeze A into B- the reaction produces CO2 in B which increases the pressure of B.

5) Mix enough of the mixture and the pressure will eventually be high enough to be 'pushed' into A.

6) When it gets to the required 1.5 kg/cm2 pressure in A as required- release the valve to get your required bubble speed.

7) When the pressure in B drops below A (since the CO2 is being let into the tank), it'll draw mixture A - which creates more CO2 and increases the pressure. The cycle repeats till there's no more mixture A left.



Tips:



1) Use very warm water to dissolve the citric acid and sodium bicarbonate.

2) The video that I watched said that you should open the valve to make it easier to squeeze A. I notice you waste a LOT of the mixture if you do it. It is a LOT harder to squeeze A whilst keeping the valve close- but you're saving on your mixture (not recommended for arthritic hands). Actually, after capping A and before capping B-I insert about 20g of citric acid straight into B then quickly cap the bottle off to jump start the system.

3) BE PATIENT!! When you squeeze A into B, wait until no more bubbles are produced in B and no bubbles go into A. Swirl it if you have to speed it up. But wait. Once, I just kept squeezing A to get the right pressure without waiting and the pressure in A kept on building to almost 4 kg/cm2- 3 hours after I left it alone.

4) Via trial and error- I use 200g of citric acid to 400 ml of water and 200g of bicarbonate to 600 ml water. If you use a lot of water initially- towards the end, all the water would accumulate in B and the pressure can go up very quickly overnight. Less water= more room for the gas. Using it at about 0.8-1 bubbles per second for 8 hours a day (I attached a solenoid valve with no issues), I usually get about 2 weeks supply. Which comes to about £4.5 per month with 100g of citric acid to spare (minus what you put in B to jump start the system). If you use less water (200ml as stated)- even a tiny bit of the reagents mixing will lead to a quite rapid pressure rise.

5) There were a couple of times when the pressure in A was around 4 kg/cm3 and climbing- I just SLOWLY unscrew the top off and stop when I heard the hiss to release the excess gas. It was safe for me- use the tip at your discretion.



All in all, a cheap alternative to my pressurised kit. But will certainly go back to the pressurised system when it's repaired. Kept on worrying about the build up of gas and worse case scenario it exploding. As for all DIY system, know what you are doing.