Hairlike worms and critters in tank?

About a month ago I moved to another apartment and within a week I noticed small, pill bug type critters crawling on the walls, gravel, and plants. They are really so small, you almost don't notice them except for the fact they are in huge numbers.They seemed to be interested in the algae only, they were not on the fish. I took the critters to the pet store and they didnt know what they were. I was sold an anti-parasitic tablet. This didnt help in the long run. The next day I also noticed small white hair-like worms, about 1/4 inch long, crawling on the gl and floating in the water. They crawl on the gl in an inch worm motion. They do not seem interested in the fish either. I have cleaned my tank, and changed the water several times. I have been feeding small amounts and removing any food that goes uneaten. Are they related? What are they? How do I get rid of them? I also have a separate bowl with fry. There are neither of these creatures in the bowl.