So after months of saying i will set up a gutter on my shed to catch water on Sunday I finally did it. Haven't got a water butt yet so just put a bucket underneath just to see if it would work. The bucket was full the smorning so decided to test the ppm. 008. I couldn't believe it. Now I know some people won't clean with this high so before it got dark I filled my spare backpack up & cleaned one of my windows. Came out fantastic. Not a spot in sight. Well impressed.