The one nutrient issue that I've run into in my ten some years growing hydroponically is the concentration issue. You can't have a liquid concentrate of hydroponic nutrient solution that delivers all the nutrients you need (at least none of the systems I've tried works as a single concentrate). The reason is that in concentrations some of the non-organic ionic compounds will change their loyalty and chemically reaction with other ions to precipitate out some of the important nutrients. This is undoubtedly a complex concentration related and perhaps pH related process as well, but take my word for it.
The result is that if you get nutrients in concentrated form but multiple solutions, there's a reason. Don't mix them in concentrated form. Instead add them separately to your diluted nutrient solution so you don't precipitate out any of the ionic compounds.
This also applies to single nutrient concentrates delivered in powered form. If you try to make life simpler by mixing them up in a concentrate they will precipitate out some of the nutrients and you'll end up with nutrient deficiencies. I know. It happened to me and I didn't realize what had happened until I read the fine print. Of course the fact that my plants were all deformed was a clue.