Fluval Sea Hydrometer by Pet O Pets
The Fluval Sea Hydrometer provides an accurate and convenient method of measuring specific gravity and salt level in marine aquariums. Regular testing is strongly recommended as stable salinity levels are essential for the health of marine fish and invertebrates.
Compact and easy to use, the hydrometer can be permanently installed inside the tank for continuous readings. Its slim, low-profile design camouflages well inside the tank and will not diminish the aesthetics of the aquarium. It can also be used as a portable device, allowing you to take samples simply by submerging it in the water.
It features large, easy-to-read markings with the ideal salinity range clearly marked in green for clarity.
| Feature | Detail |
|---|---|
| Measurement Type | Specific gravity and salt level |
| Installation | Permanent or portable use |
| Design | Slim, low-profile, tank-friendly |
| Readability | Large markings with green-highlighted ideal range |
FAQ
Can the hydrometer be left permanently in the aquarium?
Yes, the Fluval Sea Hydrometer can be permanently installed inside the tank for continuous monitoring of salinity levels.
Is the hydrometer suitable for both saltwater and freshwater tanks?
No, this hydrometer is designed specifically for marine aquariums and measures salt levels in saltwater environments only.
How often should I calibrate the hydrometer?
Please contact customer service


Gavin Grant –
I installed the hydrometer directly in my 55-gallon saltwater tank. It’s very discreet and doesn’t look out of place. The green marking for ideal salinity is easy to spot. I check it weekly and it’s helped me maintain stable water conditions.
Liam Dowd –
Works well as a permanent fixture. I found it easier to monitor salinity without having to take samples. The markings are clear and the design blends in nicely with the tank decor.
Anne Nash –
Great tool for a beginner. I used it to test water before adding new fish. The portable feature is handy when I need to check salinity during tank maintenance.