Steve, thank you for the info, i really was only relying on iodine’s dark brown color to guess the frequency range… I have a limited knowledge in this area…
sacred, Lightning thank you! I will not re-plaster the cone then and keep it as is 
I tried to feel the energy through the crystal opening and didn’t feel a difference between the top and the side… 
this probably comes with practice…
I really like the idea of the black walnut hulls as a iodine source, thank you will look up more on that. I am hesitant to supplement with seaweed in large quantities, as i am concerned about the pollutions/heavy metals, but the black walnut should be good then…
Anna