So
advanced Nutrients Rhino Skin, which is 1.5% SiO2, is not readily available in a
Current Culture RDWC?... Even with microbial and fungal supplements?
Is that what you're saying?... that silicic acid is necessary?
this is how i take it
In most hydroponics applications, silicon is added to the nutrient solution as potassium silicate. Potassium silicate is water soluble, but it reacts strongly with concentrated nutrient solutions, forming an insoluble, glue-like substance. So when using silicon additives, make sure that they are added in dilute form, not directly to the concentrated fertilizer! 50-100 ppm is a good target for most applications.
Potassium silicate is also very alkaline in nature, raising the pH of the nutrient solution. Raising the pH can be beneficial if the pH is below 5.5, but most water used for irrigation is already too high for optimum plant growth. So when using source water that is high in bicarbonates, adding additional silicon could worsen the pH problems, making it necessary to add too much pH lowering products such as phosphoric acid. In extreme cases, high levels of phosphoric acid could lead to phosphorus toxicity.
Silicon dioxide, derived from diatomite, is an acceptable alternate to potassium silicate. Although silicon dioxide (SiO2) is not very soluble, finely-powdered forms are “flowable” and become readily available to the plant. The main benefit of silicon dioxide, besides being derived from a natural source, is that it does not have a negative effect on pH. It is relatively pH neutral in most hydroponic and soil applications.