I've not seen anyone talking about a product I use called Algon for a few years & wanted to say how fantastic it is at this time of the year. I've been using it for cleaning the algae & moss from my patio for a few years & it's great. Works really well if you power wash first then just spray it on & leave it to work. It's stopped the slippy surface as well as the green build up which is great for the children as they run around & it's not great when it's so slippy so if anyone is looking for something to help clean patio/path algae I'd try using Algon. Their website has more info on it as well if you want to look at it 'Algon'
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Happy Gardening Shrubs