iīve cleaned pools for a few years and found that customers are reluctant to let me dilute their pools in order to control cya (water is expensive here in spain). the result is that it used to be really difficult controlling algae with high levels of cya.
having spent much time shocking with liq chlor, dabbling with bromine and testing numerous algicides, i eventually found that using copper based algicides were the only way of preventing algae when cya levels were too high.
as many posters on here are from the other side of the pond, i wondered if there is the same difficulty in persuading pool owners to dilute their pools? iīve tried explaining how swcgs make it easy to control cya but customers tend to be put off by the price of a salt system.