cal-mag 4 rain water?

96tears · Feb 14, 2020

I have a indoor soil grow and have captured Rain Water and was wondering if adding cal-mag is a necessity or a option?

EliteCultivation · Feb 14, 2020

It's an option.
Rain water has a higher content of calcium and magnesium so cal/mag should only be added if necessary.

Chip Green · Feb 14, 2020

My rainwater, was showing less than 10ppm. As does any reclaimed snow, in my experimentation.