Quote Originally Posted by rak70
...He says I'm reading it wrong that the max is 100ppm and you have to subtract what you see on the scale from 100. Hence if you have a reading of 100 it really means 0 and if it reads 0 you really have 100.
The scary part about this is what about the poor sap who brings in his sample that actually has 90 ppm of CYA and does not know any better so he takes the 10 lbs. of CYA the guy sells him...

Dave