The Live pH in-tank meter takes Mardel test strip water monitoring into your aquarium, making it even easier to maintain healthy water quality. Liveph helps you maintain healthy water by constantly monitoring pH and providing immediate response to harmful pH changes. Just attach LivepH to the inside of your aquarium using the suction cup. Then just glance at the active membrane on your LivepH meter to determine pH values. Patent pending technology ensures accurate pH values. For freshwater aquariums only. Replace meter every 4-6 weeks. This 3 month supply package contains: 1 LivepH meter, 2 strip refills and Fish Care Guide. Shipping weight: 1/6 lb.