Tetrafauna Happy Turtle ReptoGuard is a medicated sulfa block that treats water in turtle tanks and amphibious terrariums to help control common diseases. Slowly dissolving block is ideal for use with aquatic turtles, amphibians, and other reptiles. Medicated sulfa block treats water in turtle tanks and amphibious terrariums Helps control common diseases for a happy turtle Slow release ReptoGuard medicated sulfa blocks also help control common waterborne diseases including salmonella.Lasts up to two months. Each block is approximately 2" in length.