kelpak and physan 20 in the eu?

[Dusty Ol' Man]

Originally Posted by estación seca

Many algae secrete a chemical matrix which keeps chlorine and other things away from the cells, and helps algae adhere to things. I suspect it would keep quaternary ammonium compounds out, too. It can be very difficult to get rid of wall algae. Talk to pool owners.

I suggest really scrubbing your tank for a long time with a higher concentration of bleach, and leaving it soak for a while. If it's glass you can bake it in the oven at 250 F / 120C for an hour.

Thanks. Unfortunately, it's plastic. I'll just increase the frequency of cleaning it.