There was less than 500g in the barrel I used, which was slmist filled with water. No idea of the volume but the blue poly barrels are pretty standard I'd think.
I ebded up sourcing mine as a 500g packet from a farm animal supply. Still have just a little bit left for other experiments.
I'm leaving all the typos in there as a historic relic for futere anthropologists to comment on the stupidity of tiny touch screen keyboards.
LOL! It could have been worse, I've seen some proper auto-spelling-correct howlers in recent times. My phone has a complete aversion to the word "van", preferring "can" instead...
Anyway, I think I've solved the cold problem:
The only problem with it is it's supposed to use screw-in gas canisters; so I'll knock up an adapter for it at some point to use a propane bottle... Pop that under the bath, light, add some more citric acid for extra flavour, slap a top over it, and we should be bubbling away nicely in no time
And at only £6, if one isn't enough it's cheap enough to buy another one. Or two...