We always mix our chemicals instead of buying premixes. It's usually much cheaper to mix your own. And then you can use generics and make it way cheaper. Also easy to make blend to what you want. Maybe you want more or less of a certain chemical than what is in a premix. It's a little more work and handling more chemicals, but I do it to save $$$$$. Premixes are the easy button. Less figuring out amounts and handling. Dump in jug and done. More $$$$.