If the brand of nutrients is not listed on the webpage, you need to reach out to growdiaries and ask them to add them in, however this is not always free, and the brand may need to pay growdiaries a fee to be listed here, IMO its not worth the money, just add them in as custom fertilizers and give credit to them in the text of your diary. This is what I do for brands not listed on the site.
growdiaries.com/contact