It sounds like you guys are all a bunch of sticks in the mud.
My furnace doesn't have a warranty so I'm not worried about that. I also found that companies put in potassium hydroxide (a very strong base) to control pH. I've added that and some pH test strips to my list of needed items.
I've collected more MSDS sheets and all of them list pretty much the same ingredients. None of them say exactly how much but I've got enough to go on.
For one gallon of water I'll add 5-10% by weight sodium nitrite (nitrite, not nitrate as I said earlier, oops). After that has time to circulate I'll use the same method to add sodium hydroxide as needed, 1-5% to a gallon of water.
Some companies have die that just makes their product pretty. It's not an accurate representation of when the chemicals lose potency.
And so you all know, a gallon of this stuff costs about $5 to make, on the high side. It's probably less. The chemical companies and the boiler companies are both making huge markups. I understand that you're maintaining your warranty and stuff but most of those are worthless anyway, especially after the initial coverage period.
Cheers.