So I have been hesitant to rake that metal putty knife that comes with the form1 across the bottom of my tank. I looked around the house for a substitute and found the perfect tool. I had a leftover wallpaper smoothing tool about 6" across made from stiff rubbery plastic (PME I think). I cut mine in half as its easier to use that way and it works like a charm. I use it to stir my resin and check the bottom of the tank for cured resin bits and cloudiness - which it does with a little pressure while holding the tool at a 45 degree angle. A few swipes back and forth across the whole tank in both axis and done.
I had found mine at the local DIY in the paint and wallpaper tool section. Similar tools are also used in cake decorating like this one - http://www.amazon.com/PME-Smooth-Scraper-Smoother-plastic/dp/B005G03DDK
Regards,
BW