This is what they say on the bleach labels for current chemistry:

BL3.20 bleach (for 20 litres, three parts)

Part A
"with no more than 51% acid"
Sulfuric Acid
Sodium 3-Nitrobenzene Sulfonate (CAS 127-68-4)
Water

Part B
Ethyl Diglycol
3-Mercapto-1-Propane Sulfonic Acid (CAS 17636-10-1)
Potassium Iodide
Sodium Bromide
Sodium Iodide
Quinoxaline Derivative 7 (CAS 17635-21-1)
Water

Part C
Potassium Carbonate
Sulfonated Trialkylphosphine (CAS 86563-95-3)
Water


BL30.2 bleach (for 2 litres, single part)
Ethyl Diglycol
Sulfuric Acid
Sodium 3-Nitrobenzene Sulfonate (CAS 127-68-4)
Water

One can only guess why the single part contains significantly smaller number of chemicals. Could it be only because of the labelling requirements?

Andres