I don't know if it's the norm, but for me, I purchased CSB+B plus iron and it hasn't showed an improvement over flourish.
My tank is still showing a signs of iron issues. I know it's not the Ca or Mg. But since I can't test for iron, I can't be sure its iron. My UV unit is off too to make sure it's not that hampering this uptake.
I been dosing with CSB+B plus iron and the tank is still showing iron issues (it has been a couple of weeks). I add 2x the recommended flourish Iron into the tank last weekend and things started to perk up.
I wonder if it's because my phosphate is around 2 and it's bonding with the cleated iron.
My new plan is instead of running a weekly schedule; I'm going bi-weekly. After every dosing day, it will follow a non-dosing day. Maybe this will help, don't know for sure. But I'm going to find out. (I think I saw Tom Barr post something this, but can’t seem to find it.)