Michika,
Maybe we are talking about different product, I use Tunze two part stuff .
http://www.jlaquatics.com/phpstore/s..._ID=tz-z010474
You need to mix two together and it becomes purple color. Its like a wet clay but harder.
You have about 9-12 minutes to get the job done.
I get the film on the surface but with amount of serface agitation i have, this is nothing. No smell from this thing at all. The only thing i do Not like is that skimmer goes nutts for a day and i need to rase my skimmer cup.