Two main factors should be considered when setting up reef aquarium water: the salinity and water movement. The first step is getting the chemical balance correct to mimic natural salt water, known as NSW among reef aquarium owners.
If you are converting freshwater to saltwater using a sea salt mix, look on the label to make sure it contains the elements that are contained in salt water: chlorine, sodium, magnesium, sulfur, calcium, potassium, bromine, boron, strontium and silicon. On the label, make sure the sea salt mix includes these elements and no other impurities or chemicals. Experts disagree on the best brand of sea salt because what works depends on the chemical composition of the water you start with – every town and city’s water has varying chemical make-ups.
Once the reef aquarium water has been tested for salinity and it is ready, you want to next consider water movement in the tank. Reef tank experts suggest a water turnover rate of 10x: 10 x aquarium capacity in gallons = required flow in gallons per hour. However, some corals need different water flows. Some corals, like the mushroom coral, require little water movement.
On the other hand, some monitpora varieties need medium water movement in the range of 30 to 40 times more flow. This volume of movement mimics waves breaking at the surface of water – in nature, montiporas are most often found in shallow warm water in lagoon-like conditions. They also rely on photosynthesis, like all corals, so being close to the surface to attain the sunlight is important. Water flow is how corals get food to make up for what they can’t develop through photosynthesis. Further, water flow regulates water temperature so that corals don’t experience thermal shock from colder water than what they are used to in nature. Corals thrive in water that is between 72 and 78 degrees Fahrenheit.
To ensure proper movement of reef aquarium water, pumps will need to be considered. Most reef aquarists use an overflow. This system drains the water into a sump and then the water is pushed back into tank. Most tanks come equipped with the pre-drilled holes so that you can set up an overflow or pump system. Another way to create water movement is by using multiple power heads which act as small underwater water pumps. These pumps can be turned off and on with a timer to mimic different water movements over time. Propeller pumps are also popular. They can move a lot more water for larger tanks. They move water without a direct force of a power head, therefore using less energy. However, they are more expensive than the other water movement options.
A newer water movement option is the gyre tank. In this model, the tank has a divider in the middle of the aquarium which encourages a maximum amount of water movement. The divider makes an open space that leaves little room for friction against water movement. This method is also a successful way to make water movement in your reef aquarium.