Removing Algea Build-Up

[lifegardener]

We have some canvas covering over a garden area that gets occasionally damp - and noticed algea forming on it.

Vinegar appears to have helped a bit in removing some of the algea stains, yet some of the stubborn ones remain.

Any suggestions on a more effective approach are appreciated.

 

[DirtMechanic]

Try oxi clean, sodium percarbonate. Maybe hydrogen peroxide but oxi is stronger.