snrub thanks for your explanation and research. I think I learned a few things...
1. I do get a generic 41% concentrated RU by the gallon online. Since it is an offbrand (but best seller online) I don't know for sure if it is truly 41% or not.
2. I think weather conditions may not have been perfect when I sprayed. (no rain, but towards evening when sun going down when pores of plants may have closed?)
3. I can't be sure if there was a partial batch left in the 3 gal sprayer so it may have 'bound up' to the bad water.
4. The water was hard water when I mixed it.
Next time I'm doing distilled and a fresh batch each time, plus spray when the sun is shining!
mutant/hardy plants may be true as well since the grass I don't want to have die is always instantly dead with even the slightest mist of overspray
I'm mostly tackling semi-woody plants that grow under the edge of the tree canopy and poison ivy. They probably are tougher to kill anyway.
