i actually answered part of my question. found this in their FAQ section.
http://www.alliedprecision.com/faqs.htmlso theirs are basically designed to run between about 40-55*.
i'm inclined to buy that other de icer being that it supposedly runs 35-45. is a 10* temperature change going to shock the fish? granted its not instant but i don't want to stress the fish out. am i better off buying one of those smaller aquarium heaters and just let it run all the time and use the deicer as a backup thaw method, or go for the tried and true heat lamp method?
i just really like the idea of the deicers because you can leave them plugged in and they will regulate it for you