actually they sound like spirobide worms, small calcified creatures, less than 2 mm, attaching to glass and rock. THEY are a pain. I squish about 50 per day. I have heard of nothing but mechanical removal. DO NOT let them get to plentiful. Your tank must be in good nick as the are somewhat fussy. To reduce their numbers you can also reduce the food your're feeding. I have a double layer fine net that I clean the tank with 5 minutes after feeding, and the pumps are back on. Another way is to rinse any shrimp/ live food and strain with a net to get rid of the small particles of food, which keep them going.