This is what i want to learn just to reading properly from plants. And i think i will print some things to have little cheat sheet under my hand.That is why I like the <"Duckweed Index"> you just watch the plants - <"Duckweed Index questions"> and from there you make all your decisions <"based on plant growth">.
I want to try them with that calculator to make proper calculations but I don't have an excel for the moment.Your tap water is moderately hard and nitrate (NO3) rich, this means that you can add less of @GHNelson 's fertiliser and you may have issues with iron availability, @keef321 is your best bet for information. He has <"seen it, done it"> and now has the tee-shirt.
Thank you