"Sacha" wrote in message
. uk...
Thanks, Nick. That should help the OP sort it out. We have to clean off
some of the slabs here because in wet weather they become v. slippery.

That's exactly why I am keen to clean up now, we have a holiday apartment
adjoining the house which we let and the path to that becomes VERY slippery
when wet if I don't clean up the algae.

Mike
www.farend.org.uk