I have run into a couple of reports of using silver based algaecides to deal with persistent mustard algae after other procedures had failed and to kill black algae.
Silver based algaecides, like Silvertrene, are expensive and difficult to find. The cost alone argues against using silver based products for anything but the most extreme situations.
I was wondering if anyone has any thoughts on using a silver based algaecide for dealing with black algae, which can be rather difficult to kill. Traditional methods of killing black algae are either very time consuming, or expensive, or both and don't always work. If a silver based algaecide works for black algae, it could be worth the expense.