When most people plan to start their first ever saltwater and reef aquarium they have a notion that water parameters in a saltwater environment is a difficult topic. However, I believe this is just a notion and the truth is quite different.
If you go into the in-depth complexity and analysis, things may seem to be all confusing, but why should you anyway do so? You can easily succeed by having proper knowledge of the basics. In fact, I will now share with you what I have learned about the water parameters for reef tank. If you too just follow this approach, you yourself will realize that things really are not all that difficult.
The parameters here shall be divided into two categories – Critical and Non-Critical, each with their own subcategories for you to explore.
Summary of The Parameters With An Infographic
When I say salinity I am referring to the amount of salt present in the salt water. There are different methods to measure salinity including hydrometers, refractometers, and probes. Another way to measure salinity is to take one liter of saltwater, evaporate it, and then weight the salt that is left.
No matter what the measurement technique, the exact unit derived is not always used by the aquarists and in fact they are used interchangeably. What I have mostly seen is that in the case of reef aquaria the salinity levels are generally kept lower than natural.
The salinity levels of natural ocean water are 35 ppt, corresponding with a conductivity of 53mS/cm and gravity of nearly 1.0264. Dr. Ron Shimek’s suggestion and also what I would recommend is to keep the salinity levels in your aquarium as close to the natural one as is possible.
Most of the inhabitants that we keep in our aquarium come from tropical reefs. What I would now like to share with you is the fact that tropical reefs have a stable temperature ranging between 83 and 86 degrees Fahrenheit.
If you live in a place with a steady tropical temperature, as was just mentioned, then great. But if you are like me, not that lucky, then you will need an aquarium heater to raise the temperature of the water and prevent falling it from the required levels.
If you reside in a humid and warm climate, wherein the temperature goes higher than the required range then you will have to invest in an aquarium chiller.
Okay, I will not go too deep into the details regarding what pH is. But what you need to know is that pH levels help you understand how acidic the water is (or is not for that matter.) You need to aim for a range of something between 8.0 and 8.3, and you need to make sure the pH remains stable.
If there is too much swing in the pH level then it can prove to be unhealthy for the little creatures. The ocean’s pH levels have gone from 8.2 to 8.1 since the industrial revolution and will likely go down further. Though we cannot do much about this, if the pH level in your aquarium goes down or above the desired range then you should never forget to adjust the same to avoid your corals and fish from getting a shock.
Alkalinity helps you figure out the amount of bicarbonate present in water, and this is important for the health of the lives in our reef tanks. Alkalinity needs to be in the appropriate range (8-12 dkh for a reef tank) to make sure there is enough bicarbonate for the corals to grow.
I would suggest finding the alkalinity level (within the range suggested above) that is easy to maintain and suits the creatures in your tank, and once you have found it, remain consistent. The consistency is important to help prevent the inhabitants in your aquarium from getting shocked. Basically you just need one of the best reef salts available in the market. It will do the rest of keeping a certain alkalinity level.
Ammonia is excreted by animals and also by our aquarium inhabitants. Sadly, it is toxic to every animals, fishes, and corals present in your reef tanks. Ammonia should be always zero in your aquarium.
In a properly cycled aquarium, the ammonia will be consumed immediately by the beneficial bacteria colony established in the live rock or bio-filter media. So an aquarium test kit should give you zero reading for ammonia. Consumed ammonia is broken down into nitrite, which is less toxic but yet harmful for aquatic beings.
Phosphate is present naturally on reefs at a level of 0.13 ppm. Even at its natural levels, it can spell trouble. Phosphate acts as a fertilizer for algae in your saltwater aquarium. It is kind of tricky to find out the ideal phosphate levels for your tank. As it causes algae growth you might want to keep it near or at zero. But, it serves as a nutrient too for corals, pods and zooplankton. I would recommend keeping it below 0.2ppm, if possible.
Calcium is very important in a reef tank and is good for coral health. Yes, they have no bones but they have bony skeletons that are made up of calcium. Natural coral reefs have calcium levels somewhere between 380 and 480 ppm. That is a pretty narrow range and to make things easier for you I would suggest maintaining a level of about 400 ppm.
In marine aquarium the reef salt will keep the desired calcium level but in a reef tank the calcium will be consumed fast by the corals. So, you may consider buying a calcium reactor or dosing pump to maintain a constant calcium level.
Magnesium interacts in a certain way with the alkalinity and calcium balance in reef tanks and thus gets its importance. Aquarium water and seawater are supersaturated with CaCO3 (calcium carbonate) and this is mostly because of magnesium. As soon as calcium carbonate starts to precipitate, magnesium attaches itself to the growing crystal of CaCO3. The surface of the crystals is clogged, and then they are not able to attract more carbonate and calcium, and the precipitation stops.
If it was not for magnesium then CaCO3 precipitation would reach such a level that the maintenance of alkalinity and calcium at natural levels would be difficult. This is why I would recommend a natural seawater-like concentration of magnesium (1285 ppm.) A range of 1250-1350 or even a level slightly outside, of about 1200-1400 ppm, will be okay.
Nitrite is a by-product that is produced while the ammonia is being consumed by your bacteria colony. Nitrite is less harmful than ammonia but it is still toxic and ideally should be zero in your reef tank. Thanks to another type of bacteria that are also available in a cycled tank, consume this nitrite and produces nitrate during the process.
Nitrate signifies the right working of the biological filter of any properly cycled aquarium. You need to keep the nitrate levels really low. Anything between 30-40 ppm would generally be acceptable to most of the saltwater tank fishes and also most soft corals. Though the ideal level is 0 ppm, slightly higher levels, as was just mentioned, will also do fine.
Iodine is essential for cellular function and nutrient transfer within the cell. Corals need Iodine for the synthesis of pigments, which allow them to adapt under varying light conditions. It also protects their tissue from UV radiation. Invertebrates with exoskeletons (mainly shrimps and crabs in the aquarium) require iodine for molting and forming new exoskeletons as they grow. To maintain an ideal iodine level you have to first understand the consumption rate of your tank. However, a level of 0.055-0.7 ppm will be fine in most cases.
Recommended strontium levels in reef tank water is between 5 to 15 ppm. Aquarists should not add strontium before they first measure the strontium levels and find it to be less than 5 ppm.
Silica helps in the growth and health of organisms like mollusks, diatoms, and sponges. If diatoms are an issue in a reef aquarium then it can signify the presence of soluble silica, particularly through tap water. If you purify the water the problem should be solved. If, however, diatoms are not an issue then we would suggest to add soluble silica because the creatures in our aquarium require them.
The importance of boron is not usually discussed and it actually is not an essential element that you have to control in your tank. It just appears as a necessary nutrient for some organisms and can be toxic to some at certain levels. I would thus recommend maintaining a natural level of around 4.4 ppm.
Some important tips
- Remember, test kits can fail, so keep observing your tank time to time.
- Make sure your glassware is clean, or else, you may not get accurate test results.
- If you notice the nitrate reading is high but your tank tells you otherwise, change the water and get another test kit.
Just investing in an aquarium is not enough and your responsibility does not end there. You also need to take good care of it. The parameters that I have shared above will help you understand more about saltwater and reef aquarium requirement and maintenance, and make things a lot easier for you. Just follow these parameters and you will always be the proud owner of a beautiful aquarium, with healthy and happy lives within it.