Keeping proper reef tank parameters is essential for the health of your fish, coral and other invertebrates. High Nitrates & Phosphates can lead to unsightly algae and fluctuations in your levels can lead to poor coral heath. Some levels can even cause coral and fish death.

We have created this handy reference to help you achieve the parameters you need for a thriving reef and the reason behind the choices.


Ideal Parameters for a Fish Only (FOWLR) tank (in order of importance)

Salinity: 1.024-1.026 SG (it is possible to run lower in fish only)
PH: 7.8-8.2
Ammonia: Less than 0.1ppm
Alkalinity: 7-12 Dkh
Nitrite: 0ppm
Temperature: 25-26 degrees C (some fish prefer a cooler level)

Phosphate: Less than 0.04ppm *
Nitrate: Less than 20ppm *
Calcium: 380-450ppm *
Magnesium: 1200-1400ppm *


* In a fowlr tank some parameters are less important, Calcium, Magnesium for example wont fluctuate much without corals to consume them, Phosphate and nitrate will cause algae but again having perfect parameters isn't as important in a fowlr tank.

 

Ideal parameters for an SPS LPS or Mixed Reef tank

Some places will give you different levels for an SPS Dominant Reef, LPS Dominant Reef and Mixed Reef aquarium, but we prefer to settle to one set of parameters for all of these. There are instances where you can vary some of these and we have outlined some of the reasons for this later in this post.

Salinity: 1.024-1.026 SG (we aim for 1.025 so there's a tweak of leeway.)
PH: 7.8-8.2
Ammonia: Less than 0.1ppm
Alkalinity: 7-12 Dkh (see note about alkalinity importance below)

Phosphate: Less than 0.04ppm
Nitrate: 5-8ppm
Calcium: 380-450ppm
Magnesium: 1200-1400ppm

Iodine: 0.06ppm
Strontium: 7-9ppm

there are many other trace elements, an ICP test would give you a great indication of what levels to run these at but testing for them isn't something you would do on a general basis.

Additional Information and Emergency situations.

Alkalinity is more important in reef tanks than fish only but a low alkalinity can contribute to low PH which will affect fish health so keep your DKH above 7 where possible. In a system with coral its not the exact number that's important but stability, keep your reef levels especially Alkalinity as stable as possible, if your DKH is 8, then try and ensure its 8 all day every day.

Something we generally recommend with Alkalinity is simply to match your salts levels. For example we use Aquaforest Reef Salt in our systems, its just a personal preference there's loads of different salts available. Usually this salt mixes with a Dkh of around 7.5 as a result we tray and maintain all our tanks with a DKH of 7.5 Now some of these tanks are not even water changed and levels are maintained with dosing, but what if there was an issue and we had to suddenly do a large water change? By matching our salt this isn't a problem and a large water change wont cause a fluctuation in parameters.