In particular, its a pernicious black type that grows in 'spots' that resist
all but the most determined powerwashing, in fact the concrete goes at the
same time. Power washer, bleach,and jeyes fluid are all proving no match.
Any suggestions? Are there algae cleaners you can buy that are any better?

--
Tumbleweed

Remove my socks before replying (but no email reply necessary to newsgroups)