344mg 2-4 times a week if you want EI levels. If you have another iron source in your micro's you might want to cut back a bit. The only thing to avoid dosing/mixing with iron is phosphates because they will precipitate out.
http://rota.la/ is a great calculator...set 20 gallon, DIY, select DTPA 11%, dry dosing and The Estimative Index to get the values I gave you.
http://rota.la/ is a great calculator...set 20 gallon, DIY, select DTPA 11%, dry dosing and The Estimative Index to get the values I gave you.