My G25 Nature 2 cartridges hit $120 this year so I started searching for:
1. Cheaper cartridges.
2. Proof that it is worth the money.
Whilst searching for the proof, I discovered the BBB method and started researching that.
Across several forums, I got conflicting information about superchlorination and Potassium Monopersulfate.
Some say one or the other gets rid of the organic but not the inorganic and vice versa.
Some say using Potassium Monopersulfate creates nitrates which feeds the algae.

But I can find no chemical reaction diagram of what happens to combined chlorine when hit with either method to see what remains after the reaction.

Does anyone know?

The curiosity hit after the accusation of Potassium Monopersulfate and algae as I started using it 3 years ago and the bottom of the pool and a spot on the side wall is black ... but no scrubbing gets it off the vinyl. I had attributed it to the black underside of the winter cover which had disintegrated over the years, but the pool guy thinks it is black algae growing through the vinyl from the ground water.

Lack of info REALLY drives me crazy .... like a splinter in the brain.