This tool provides a general estimate and does not replace professional veterinary advice.
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What is the Coral Salinity Calculator?
The Coral Salinity Calculator calculates salt needed to reach target salinity for coral tanks. Water quality is the single biggest factor in aquatic animal health. Far more animals are lost to poor water parameters than to disease introduced from outside.
A well-cared-for coral usually lives somewhere between 10 and 50 years. As a filter feeder, what a coral needs from its diet changes across its life stages. Corals are colonial animals, not plants, and depend on stable salinity, alkalinity, calcium and strong lighting. They are the least forgiving part of a reef tank, where stability matters more than any single value. Health problems that show up most often in corals include bleaching from heat or light stress, tissue recession from unstable alkalinity, brown jelly infection, which is part of why tracking this over time pays off.
Coral quick facts
| Measure | Coral |
|---|---|
| Typical lifespan | 10–50 years |
| Diet | Filter feeder |
| Mature at | About 3 years |
| Clutch size | 0–0 eggs |
How does the Coral Salinity Calculator work?
The figures are based on commonly cited aquarist rules of thumb and safe parameter ranges for corals, scaled to your tank or livestock details. Treat the result as a well-founded estimate. Every coral is an individual, and your vet's judgement outranks any online tool.
Factors that matter
- Tank size and current stocking level
- Filtration capacity: which affects how much waste the system can safely process
- Feeding habits: since overfeeding is a leading cause of poor water quality
- Source water quality before treatment, which varies by location
How do you use the Coral Salinity Calculator?
- Enter the current specific gravity
- Enter the tank volume in whichever unit you use (US gal, L, UK gal)
- Enter the target specific gravity
- Press Calculate, then read the result alongside the sources listed below
Bring the number to your next appointment. Vets can work with a figure and a date far more easily than with "he seems a bit off lately".
For related questions, see the other water tools or browse every coral tool.
Before you rely on this
This calculation assumes a healthy adult coral with no complicating conditions. Pregnancy, recovery from illness, medication and significant age at either end of the scale all change what is appropriate. When in doubt, the safest move is to take the number to a vet and ask whether it fits your particular animal.
Sources and references
The formulas, reference ranges and species data behind the Coral Salinity Calculator come from these veterinary references, professional bodies and published research.
- University of Florida IFAS ExtensionAquacultureedis.ifas.ufl.edu(opens in a new tab)
- Merck Veterinary ManualReptilesmerckvetmanual.com(opens in a new tab)
- ARAVAssociation of Reptilian and Amphibian Veterinariansarav.org(opens in a new tab)
- Merck Veterinary ManualExotic and Laboratory Animalsmerckvetmanual.com(opens in a new tab)
- Merck Veterinary ManualRoutine Care and Breedingmerckvetmanual.com(opens in a new tab)
- Built on veterinary referencesFormulas and ranges come from veterinary manuals, university research and welfare bodies, listed above for you to check.
- Instant resultsNo page reload, no waiting and no account. Enter your details and the result appears straight away.
- Private by designCalculations run in your browser. Nothing you enter is stored on our servers or shared with anyone.
- Always freeEvery XpertsPet tool is free to use, with no premium tier and nothing to sign up for.