[stuartb]

4% doesn’t sound like that much difference but do people find the 15% far superior or nothing really in it?

[Smudger]

if your diluting it then 14% will last longer than the weaker equivalent

but if your spotting a very bad area then 14% all the way

Darran

[Mike Halliday]

That 4% makes it nearly 33% stronger ( compared to 11%)