First post here so I guess I will introduce myself first and foremost.
23 years of age, lives in Sweden and newly hooked on hookah

I have a small problem with my shiazo stones.
Everytime I smoke them I get soar in the back of my throat, however when I smoke real tobacco I have no problem at all (using the same setup for both)
This is the hookah i use http://www.vattenpipan.com/produkt.php?i=745 (couldnt find it at an english site, sorry)
And these stones: http://www.vattenpipan.com/produkt.php?i=867
Tried filling the head with different amounts, tried different coals and different amount of holes in the foil. Nothing seems to help me get rid of the harshness.
And from what I can tell from the reviews, noone else thinks they smoke harsh? Or am I missing something?
Thanks for the potential help!