Thanks for posting this. I understood the basics but this sufficiently clarifies usage in detail. One aspect not mentioned, if purchasing the 3% solution it should be food grade so the solution remains stable for an extended period of time.
Not sure I am going to use this right now but wanted it on hand if needed. I picked up some 34% HP at my local hydroponics store just to have the good stuff on hand rather than the dollar store wonder what's in it HP. This ratio calculator is really nice to make small accurate batches. I have a bunch of syringes I got off of ebay and they really are great for measuring. For instance my one system has 7 gallons of water, which would be 35ml at 3% (1 tsp per gallon) and at 1:10 34%HP to water I need me some automatic math!