Fluval SEA Saltwater Levered Hydrometer
Water type
Marine
Part no.
14356
Test method
Levered hydrometer
Reads
Specific gravity, salinity
Design
In-tank or portable
Ideal range
Marked in green
Fluval SEA Saltwater Levered Hydrometer
Tells you your salt level at a glance, without mixing up a refractometer. The Fluval SEA Saltwater Levered Hydrometer is a low-profile, in-tank gauge for marine and reef aquariums – install it once and read specific gravity and salinity as easily as checking a thermometer.
Key features
- Levered float design – the arm swings against a printed scale as salinity changes, so there's no swirling or waiting for a reading to settle.
- Slim, low-profile body – sits against the glass rather than floating loose, so it's easy to hide behind rockwork or a return pump.
- Ideal range marked in green – a quick visual check without reading exact numbers every time.
- Permanent or portable use – mount it in the display for continuous monitoring, or dunk it in a sample cup at water-change time.
Specifications
| Spec | Value |
|---|---|
| Type | Levered float hydrometer |
| Use | Marine/reef specific gravity and salinity |
| Mounting | In-tank (permanent) or sample-cup (portable) |
| SKU | SEA04 |
Fluval doesn't publish an exact specific-gravity scale range or resolution figure for this model – the printed scale on the arm is the reference, and the green band marks the target zone rather than a numeric readout. If precise, repeatable numbers matter to you (for dosing calcium or alkalinity, for example), pair this with a refractometer rather than relying on the hydrometer alone.
Suitable for, and not suitable for
- Suitable for: quick daily or weekly salinity checks on marine and reef tanks, sump or display mounting.
- Not suitable for: precision dosing decisions – hydrometers of any design carry more reading error than a refractometer or a calibrated conductivity probe, especially at the edges of the scale.
Target ranges by setup
| System | Typical target SG |
|---|---|
| Fish-only marine (FOWLR) | 1.020–1.024 |
| Mixed reef | 1.023–1.025 |
| SPS-dominant reef | 1.025–1.026 |
These are general aquarist reference ranges, not figures printed on this specific hydrometer – check your livestock's needs and adjust to match.
Care and maintenance
Rinse in fresh water occasionally to clear salt creep from the pivot, which is the main cause of a sticky or slow-moving arm. Check the reading against a fresh calibration sample (or a second hydrometer/refractometer) every few months – all mechanical hydrometers drift with age and salt build-up.
Warranty and delivery
Covered by Fluval's standard manufacturer warranty against defects, in addition to your rights under Australian Consumer Law. Small parcel item – standard freight.
Common questions
Is a hydrometer as accurate as a refractometer?
No – hydrometers of any design (floating, levered or swing-arm) are less precise than an optical refractometer, and are more sensitive to temperature and calibration drift. They're a good everyday check; use a refractometer if you need repeatable, precise numbers.
Does temperature affect the reading?
Yes. Specific gravity readings shift with water temperature, so take readings at a consistent tank temperature for results you can compare week to week.
Can I use this in a freshwater tank?
No – it's calibrated for the salinity range of marine and reef aquariums and won't give a meaningful reading in freshwater.
How often should I check salinity?
Weekly is a reasonable baseline for a stable reef, more often after water changes, dosing adjustments, or if you're troubleshooting livestock stress.
