TCLyxc could answer this better than me. (Nitrogen/Phosphorus/Potassium)
As for Iron, if the ph is high, it would probably lock out any iron you add anyway.
Iron is the most common deficiency in aquaponic systems... and usually related to pH issues...
Use "chelated" iron to address the problem... "chelation" makes iron available to the plants regardless of pH (within reason)
Using Maxicrop seaweed extract, or Maxicrop + Iron... will generally provide most of the trace elements you will need..
I have never used the Maxicrop seaweed extract so I can't say how much to use. It is available on-line. Perhaps someone else will chime in and provide those details for you.