I don’t think algae can evolve bleach resistance.

Bleach basically tears apart the molecules inside the cells and destroys the proteins they need to function. Antibiotics usually exploit some specific weakness in bacteria to kill them, which can be evolved around.

If you don’t use bleach enough it’ll kill the outer layers like a film and leave harder to treat algae to dominate, but the algae can’t overcome the effects of bleach. Chlorine is smaller than cellular molecules, so it’ll always permeate.

At that point they’ll need to physically scrub the whole thing or massively increase the concentration to shock it.

Source: had a pool as a kid, when we would go on vacation we’d come back to it being green. The basic chlorine wouldn’t cut it and we’d need to buy pool shock, which was just more concentrated chlorine to kill the floating stuff, then we’d have to scrub and vacuum the algae from the surfaces.

Edit: I just checked Wikipedia, they’re using 12% hydrogen peroxide. Apparently that breaks down quickly in the sun though, so it’s unlikely to do anything for the majority of the algae.

According to pool websites you need a 35% concentration, so this is going to do nothing at all at this concentration.

So basically, an actual treatment would need literal tons of peroxide applied repeatedly. The dinky bottles they’re pouring in by hand won’t do shit.

It also is known to form a film, so it won’t kill algae without scrubbing, which they’re using army rangers to do… but even though they’re scrubbing it’s still not enough concentration to kill algae and bacteria.

It’s an either make work program or complete incompetence by a pool company that’s only worked on pools with pumps and filters. Or both.