ju1234
First off I wouldn't suggest making your own
nutrients, the learning curve for hydroponics in general is typically enough for new hydroponic growers. Then you want to add the complications of doing chemistry to the mix? Trying to figure out if any problems are because of environmental problems, or from your home made nutrients? Not to mention the start up costs for the individual mineral elements and equipment needed. Not only are there fairly cheep pre-made nutrients available, but you don't need to worry if you got the chemistry correct. I don't think you'll be able to match being able to make 500 gallons of full strength
nutrient solution for $40 total (including shipping). Much less 5000 gallons of full strength nutrient solution for about $130 (including shipping). That's just one option/source available.
If you really want to experiment with making your own, I would suggest growing them with a commercial nutrient first. Then once you've learned doing that successfully, venture into the process of making your own nutrients. If you want an idea of where to start, and the chemistry involved in making your own nutrients check out this blog:
Science in Hydroponics
The blog is written by a chemist who does hydroponics (I forget his/her name for sure (Daniel I believe). But he/she has also developed a free nutrient calculator to help with doing all the chemistry involved. The blog is kind of hard to navigate at first, but on the left side, about half way down is a drop down window under "categories" there are different subjects covered. I would need to look for them, but I do know of some online sources for the raw mineral salts for hydroponics. But if your still interested, I'll post links for them when I have time to look them up again.