So to summarize all that mobojumbo make your own with the formula supplied above, don’t fall for the expensive silica products in the hydro stores.
BTW
I do like the new product Grow-sil from build a soil, very easy to use but remember the amount of plant available silica is about the same as AGsil 16.
I tried to provide a link to Grow-sil but was unable to find it.
I noticed there are other products like it now, so take your choice.
These types of products are more natural and affect the PH less dramatically.
I have used it and I still have a little.
The main difference is ease of use, just add to your feed water and pour.
Another thing to think about is you could just add rice hulls to the soil, they claim it works better than pearlite and will add the silica to the soil for you.
The best option in my opinion is the DIY protekt formula I provided in this thread.
It is always best to do what you think is best for your situation, once you have the correct information.