Instant Ocean Hydrometer ? Accurate Salinity Measurement for Marine Aquariums Keep your saltwater aquarium thriving with this easy-to-use Instant Ocean Hydrometer. Designed for quick and reliable readings, it helps maintain the ideal salinity and specific gravity for your marine ecosystem. Features: Quick and accurate salinity and specific gravity readings Ideal for saltwater and reef aquarium setups Easy-to-read scale and steady base for upright use No batteries or power required Condition: Pre-owned and in clean, functional condition. Tested and ready to use. No cracks or leaks. Why Buy from Us? All products are inspected and tested Eco-conscious Canadian seller ? Fast and secure shipping Questions welcome! We're happy to help you find the right gear.