How to get rid of deck algae?

[teensailer]

I have been trying to clean the decks of my joint-owned Swift 18 but there are loads of dark green/black spots all over it. So far the only thing which has worked for getting it out from in between the anti slip is a metal scourer, Even that doesn’t work completely and is not going to manage for the whole deck and cockpit.

So I wondered what other people use for this kind of problem?

Thanks

 

[Seastoke]

Patio majic

 

[Dellquay13]

Patio majic

As long as the boat is ashore, the run off isn’t good at all for aquatic life.