Magnesium use by plants

[Phish Tank]

Getting ready to mix up a new batch of ferts. I started with PPS Pro level dosing last year. Have increased potassium a bit (lots of java ferns and Anubias) , and have been trying nitrates cut in half with much success. Now I'm thinking about lowering the Magnesium sulfate in base PPS Pro for this next batch.

PPS Pro base recipe contains .7 ppm weekly for Mg. It seems like remineralizing water during water changes is when Magnesium sulfate should be added, right? Or do plants actually use enough Mg to warrant it being added in macros as well?

If I have a very extended period of not being able to do regular water changes, if Mg is in my macros it would cause my Ca:Mg ratio to drift a bit and my GH to slowly creep up. I'm probably overthinking this.

I guess an unrelated question is if I should change my micros dosing (currently GLA micros EDTA+DTPA) when I know I won't be able to do a water change for an extended period. I'm planning on switching over to front loading half my macros (finally!) since that seems to make sense especially when long breaks from water changes happen.

And BTW, Thank you @Hanuman and @Zeus. ! This calculator is sooooo helpful! IFC Ferts Calculator .

 

[Naturescapes_Rocco]

Mg and Ca are "secondary" macros. I cut Mg out of my primary (front loading after WC) macro dosing, and just started using Ca and Mg as remineralizer. I keep my tanks at about 20-30ppm Ca, and between 4-8ppm Mg. I add the Ca and Mg in powder form to the tank directly after water change (I use RO water).

Works well for me, my plants, and the shrimp, too!