Flowering Cal Mag and Soil?

[Rik]

I’ve been using this flowering cal mag that has a 0-0-0 NPK that was recommended to me at the grow shop. He said it was good that it had a 0-0-0 so that it doesn’t mess with your existing nutrient plan. Here’s the one I’m talking about:

https://growhouse.supply/products/grow-more-mendocino-flowering-cal-mag?currency=USD&variant=33785464455300&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&utm_campaign=gs-2019-08-13&utm_source=google&utm_medium=smart_campaign&gclid=CjwKCAjwpMOIBhBAEiwAy5M6YEfG2bOoAox65LlT1SUKTQwEtg9ilxu6dGmlpxIqTqXzSe9X4_5XuxoCKREQAvD_BwE

Other than this, I use Fox Farm, and they have a cal mag that has a 1-0-0, and I’ve had great results with them in general so I trust them. Then, there’s one like Advanced Nutrients cal mag extra which has iron included and has a 4-0-0:

Advanced Nutrients 6360-12 Sensi Cal Mag Xtra, 250 mL.250 Liter, Brown/A https://www.amazon.com/dp/B00P8EVEHG...ZZ1CC974MFWA2F

Which of these cal mag approaches is best for soil? If I’m using Ocean Forest and the FF dirty dozen nutes, do I need to also supplement iron?

[Farmbuck]

I bought Sensi Cal Mag Xtra 4-0-0 from Advanced Nutrients but I have not use yet in my soil mix so I can't give you a recommendation. Time will will tell if I made a good choice.