Chlorine lock loves a dirty environment. Scrub the walls, brush the steps, clean out the skimmer basket. You’re basically giving your pool a bubble bath before the spa treatment.
Algae and biofilms are like little forts for contaminants. If you don’t break them down physically, the chlorine lock will just re-establish itself overnight. It’s like decluttering your house before you mop—otherwise you’re just moving the mess around.
