I will let someone else verify but if you need 36gr of micros and you need supplemental Fe, I would do 36 gr CSMB + 12Fe. I would look at how many ppm of Iron CSMB is providing and how much 12gr of DTPA would augment if added and see if it exceeds the amount you need. For me, my pH is 7.4 so the CSM , I was told only contributes 40% of the total. It doesnít disassociate from the chelator. I add DTPA to achieve my desired concentration.
I do a 500ml solution and use 5ml for a 10gal tank. In the 500 ml, I add 29 gr of CSMB and 6.88gr of 11% DTPA.