I just escaped from the dungeon of the photographic demon. I found that the following are reasonable substitutes for the standard Pyrocat B solution:
1) 100 grams Kodalk (sodium metaborate) + 30 grams potassium hydroxide or 21.4 grams sodium hydroxide + water to make 1 liter.
2) 69 grams borax + 50 grams KOH or 36 grams NaOH + water to make 1 liter.
But what is the dilution for use, 1:X:100?
"...If you can not stand the rustle of the leafs, then do not go in to the woods..."
(freely translated quote by Guido Gezelle)
PS: English is only my third language, please do forgive me my sloppy grammar...
I weigh out the Pot. Carbonate each time I make up some working solution and add it to the water first. After letting the bubbles that it releases disperse, I add solution A. Adding the borax to the water will raise the water temp about a degree C, so compensate accordingly.