You need to understand that there are more than a few things used in organics that are not themselves organic, but are organic "compatible". This is one of them. Lime is another and perlite a third.If something does not contain carbon, it is technically not organic, but its use doesn't destroy the grow's organic status.
I have never used the Grotek, but have experience with ProTekt from Dyna Gro, an excellent product. In fact, just about all of the 'organic pH-up are some form of potassium silicate. Read some labels and see for yourself. I don't use it as a pH up, but for the other benefits that silica brings to the table. Another source of K doesn't hurt eitther.
Just don't go crazy using it. 1/4tsp/gallon of water once per week, or every other week is plenty. If used as a pH up, that amount alone should be sufficient.
HTH
Wet