Raw Nutrients - SilicapH Neutral Silica An Easy to Use Powdered Additive RAW Silica contains 45% Silicon Dioxide. This form is classed as 'flowable' (or biogenic) 25 30% of it dissolves into your nutrient solution and the rest then gets trapped in the rootzone for use by the plant later on. It's pH neutral, so you don't have to deal with the potential nutrient lockout issues that can occur when using other forms of silicon (like potassium silicate). Silica works by