Pam Moore wrote:

On Thu, 05 May 2005 08:36:58 +0100, Martin Brown
wrote:

For a while - but can you stand the smell? Cheap hypochloride bleach is
another option to zap algae and probably smells less offensive.

You'd need to check this but I was once told that potassium
permanganate is a water purifier.

It is potentially, but the dark brown stain of manganese dioxide that
can result is probably worse than the original problem of the green algae.

Regards,
Martin Brown