Grott
Beer Embalmer
Hmmm, I picked up five x 4L's so I guess you got lucky.
I've lost about 30L over the past few months... thoroughly cleaned and filled a couple of kegs each brew and the metal keeps on coming through.
Can you see where the problems are inside the keg. Can you potentially waste one more 5 litres and try this-
Put 4 teaspoons of sodium per carbonate in a suitable container and pour in a good cup full of just boiled water, this will get it fizzing. Pour this into keg and top up with boiling water. Screw top on and let it sit for min 4 hours, tip out (into washing machine is good) and rinse well the keg and spear with hot water. Sanitise, put in brew and chill, carb and test.