I make my own nutrient line. And have talked to scientists and the makers of every product I use in my mix. One of my bottles contains silica SI, I get the best most soluble you can get. They are very specific on how to mix it into my concentrate. It always has to be added first! And it actually helps the higher the pH is at this time. Plus you need to mix it very well with the water before adding anything else! Once you add the other things you want to use only pH down, so go slowly and be careful not to add too much! Once you lower the pH it actually makes the silica more available to plants ...
They say the best pH to initially add it to is 11....lol
But there is no way to do that without adding oh up.
Well unless you add a secret acid that plants love which doesn't react to silica first that is....
Happy Growing....!!!!