I think I may have found out what these worms are-
Protozoa: Have you ever noticed these worms in your turtle tank? Look Closely. The best way to rid your turtle tank of these is to feed your turtles in a separate tank. Protozoa are one-celled organisms and are microscopic. There are over 45,000 species of protozoa. Some protozoa are flagellates. Flagella are long, hair-like structures that can whip back and forth rapidly, propelling the organism. Other protozoa are ciliates. Cilia are much shorter, hair-like structures that often cover the organism. Although both these types of protozoa are found in chelonians, the most commonly found are flagellates.
Even though, flagellates may not be pathogenic and may aid in the digestive system; they can easily reach pathogenic proportions in a captive environment. This parasite is easily spread by the animal drinking contaminated water and being kept in poor hygenic conditions, as is often the case when the animal suffers the consequences of the pet trade. Protozoan infections can cause acute diarrhea, dehydration, and in chronic cases, the passing of undigested food because the infection can contribute to the destruction of the normal intestinal flora
For more info go to resoasis.com