However, I would do a little more research. Maybe you have already done it without knowing it. Do you have a garden or house plants? Do they grow fine with tap water, not showing iron deficiency?
Iron is present in several forms. Combined with other elements or by itself.
Plants cannot take in and make use of all the different forms.
When iron is in the soil in the garden or in a house plant pot there are microorganisms that can make the iron more available to the plants. This takes time.
When you set up the new tank those organisms will not initially be present.
I would add a chemical that will chelate the iron and make it available to the plants. A chelator will do the same thing as the organisms do in the garden. Make the iron available to the plants.
You will have to check to see which chelator is most active at your pH.