I have never not been able to find it VERY easily. Wally World, grocery store, you name it. IDK what the issue is in FLA but here in good ol Illinausea it's all over and cheap. I actually only use it to flush the system BTW and I simply buy and use premix. Then I don't have to be a chemist. It's likely if all you're gonna do is flush with tap water you're fine, and then simply make sure the block and everything is drained very well. Then refill with proper premix product. But, if you have hard water (as I do, mine is so hard it goes so far off the chart I cannot even measure it for the softener), that it's the last thing you want mixed in your cooling system