Everbuild patio wizard concentrate everbuild patwiz1 patio wizard is a new type of mould and algae treatment that kills and cleans all type of green growth without the need for any washing off scrubbing or pressure washing totally safe and non hazardous to children and pets once dry patio wizard is made from biodegradable ingredients and does not include any bleach or acid contents 5ltr concentrate pack will cover approx 300 square metres depending on level of soiling patio wiz