BC36 Mould, Mildew, Moss & Algae Killer Ready to Use.       BC36 Mould, Mildew, Moss & Algae Killer Concentrated trade strength.       One-shot Mould Stopper 20ml - One Shot - Prevents surface mould & algae. 20ml treats 4 litres of paint.       MSR Mould Stopper 50ml - Prevents surface mould and algae.