The RO process removes minerals the plant needs so you need to put them back in.

Cal-Mag Plus is a custom plant supplement designed to help with calcium, magnesium and iron deficiencies in nutrient fertilizer programs. Cal-Mag Plus serves as a catalyst for the major elements to work in symbiosis with one another to prevent blossom end rot in tomatoes and peppers and tip burn in lettuce. Cal-Mag Plus is a bio-catalyst for plants; a highly beneficial plant nutrient supplement to correct the inherit problem of calcium, magnesium and iron mineral deficiencies found in most soil fertilizers and some Hydroponic nutrient liquid concentrated formulas. It will help prevent blossom end rot, Interveinal chlorosis, Stunted growth rates and upward leaf curl. Increases Cell division and plant tissue development, water, nutrient and carbon dioxide uptake, Growth rates and crop maturity.

Advanced Nutrients Barricade
Plants need silicon to build strong cell walls and maintain maximal metabolism. Our Barricade potassium silicate formula will substantially strengthen your plant's vigor by increasing cell wall stability and internal functions.

Thatā??s from their website, I canā??t say it any better.