Extract of Barleystraw is supplied in a 250ml bottle which treats up to 4500 litre (1000 gallons) or will give 25x10ml doses to a patio container pond (should be sufficient for one container for one year)
To calculate the volume of your pond: length x width x depth in feet x 6.25 = volume in gallons.
You may have read in the press that using barley straw (pads, bales or Extract) to prevent algae is under threat from EU regulations, despite only recently having been successfully registered as an algicide for use here in the UK. In the short term the threatened ban has been removed and we will continue to sell this good method of algae control.