Salinity map showing areas of high salinity (36 o/oo) in green, medium salinity in blue (35 o/oo), and low salinity (34 o/oo) in purple. Salinity is rather stable but areas in the North Atlantic, South Atlantic, South Pacific, Indian Ocean, Arabian Sea, Red Sea, and Mediterranean Sea tend to be a little high (green). Areas near Antarctica, the Arctic Ocean, Southeast Asia, and the West Coast of North and Central America tend to be a little low (purple).

The Nitrogen Cycle

Freshwater and Saltwater Aquariums

Aquarium Types Aquarium Types The specific aquarium setup will depend upon the requirements of the species you choose.

Basic Needs Appropriate enclosure/housing Appropriate enclosure/housing Nutrition Nutrition Hygiene Hygiene Enrichment Enrichment

Reef Aquarium

Plants Why? Oxygenation Oxygenation Waste removal Waste removal Protection Protection

The Nitrogen Cycle

Call it cycling, nitrification, biological cycle, startup cycle, break-in cycle, or the nitrogen cycle. No matter what name you use, every newly set up aquarium goes through a process of establishing beneficial bacterial colonies. The Waste Problem Unlike nature, an aquarium is a closed environment. All the wastes excreted from the fish and uneaten food stay inside the tank. If nothing eliminated those wastes, your beautiful tank would turn into a box of poison. The Nitrogen Cycle

Nitrogen Cycle Stages Summary Stage 1: Ammonia (toxic to fish) Stage 1: Ammonia (toxic to fish) Created by fish waste and/or dead fish Created by fish waste and/or dead fish Remaining uneaten food Remaining uneaten food Stage 2: Nitrites (toxic to fish) Stage 2: Nitrites (toxic to fish) Bacteria (Nitrosomonas) oxidizes the ammonia Bacteria (Nitrosomonas) oxidizes the ammonia Stage 3: Nitrates (not as harmful) Stage 3: Nitrates (not as harmful) Bacteria (Nitrobacter) convert Nitrites to Nitrates Bacteria (Nitrobacter) convert Nitrites to Nitrates Nitrates removed with gravel cleaning and water changes Nitrates removed with gravel cleaning and water changes

The cycle begins when your fish start producing waste. Their waste is quickly broken down into either ionized or unionized ammonia. The ionized form, Ammonium (NH4), is present if the pH is below 7, and is not toxic to fish. The unionized form, Ammonia (NH3), is present if the pH is 7 or above, and is highly toxic to fish. Any amount of unionized Ammonia (NH3) is dangerous. Your tank should be at 8.3 pH. The ionized form, Ammonium (NH4), is present if the pH is below 7, and is not toxic to fish. The unionized form, Ammonia (NH3), is present if the pH is 7 or above, and is highly toxic to fish. Any amount of unionized Ammonia (NH3) is dangerous. Your tank should be at 8.3 pH. Your tank needs the beneficial bacteria to break it down. Nitrosomonas and Nitrobacter bacteria can be added to the tank through an additive– or fish. Your tank needs the beneficial bacteria to break it down. Nitrosomonas and Nitrobacter bacteria can be added to the tank through an additive– or fish. When testing for Ammonia the result should always be 0, and the color yellow. When testing for Ammonia the result should always be 0, and the color yellow. The Nitrogen Cycle – Stage 1

During this stage Nitrosomonas bacteria will oxidize the ammonia, thus eliminating it. During this stage Nitrosomonas bacteria will oxidize the ammonia, thus eliminating it. However, the by-product of ammonia oxidation is nitrite, which is also highly toxic to fish. Nitrites levels as low as low as 1mg/l can be lethal to some fish. However, the by-product of ammonia oxidation is nitrite, which is also highly toxic to fish. Nitrites levels as low as low as 1mg/l can be lethal to some fish. When testing Nitrites they should always be 0, and the test result should be light blue. When testing Nitrites they should always be 0, and the test result should be light blue. The Nitrogen Cycle – Stage 2

In the last stage of the cycle, Nitrobacter bacteria convert the nitrites into nitrates. Nitrates are not highly toxic to fish in low to moderate levels. When testing your tank they should not be above and should be orange with no red hues. In the last stage of the cycle, Nitrobacter bacteria convert the nitrites into nitrates. Nitrates are not highly toxic to fish in low to moderate levels. When testing your tank they should not be above and should be orange with no red hues. Routine water changes (10% to 20% a week) will keep the nitrate levels within the safe range.. Routine water changes (10% to 20% a week) will keep the nitrate levels within the safe range.. The Nitrogen Cycle – Stage 3

The Beneficial Bacterial Nitrosomonas and Nitrobacter bacteria are slow growing surface dwelling bacterial. You can’t see them, but they live on the bio filter and the coral rock. Nitrosomonas and Nitrobacter bacteria are slow growing surface dwelling bacterial. You can’t see them, but they live on the bio filter and the coral rock. The number of bacteria in the tank is dependent on the amount of ammonia being produced by your fish. Once stabilized, the colony size will continue to expand if more ammonia is present. But because they are slow growing, it takes time for your tank to reach the third stage of the Nitrogen cycle. The number of bacteria in the tank is dependent on the amount of ammonia being produced by your fish. Once stabilized, the colony size will continue to expand if more ammonia is present. But because they are slow growing, it takes time for your tank to reach the third stage of the Nitrogen cycle.

Water Quality: Nitrogen Cycle

Unexplained Death o Dead fish and uneaten food are not always noticeable. They could drift down and be hidden in the coral or sucked up into the filter. o Make it a point to not overfeed your fish, and keep the tank, and filter clean. o A rise in your Ammonia level will be your only clue before your fish start dying.

Water Composition: Water Testing

Water Composition: Testing Fresh Water: pH pH Ammonia Ammonia Nitrite Nitrite Nitrate Nitrate Salt Water: Salinity Other: Phosphate Calcium Strontium

Water Changes Why? Dilutes waste products Dilutes waste products Corrects pH imbalances Corrects pH imbalances Can reduce algae growth Can reduce algae growth

Nutrition Dry: Flakes Pellets Sticks Floating Sinking Wafers Seaweed Live/Frozen: Blood Worms Daphnia Brine Shrimp Feeder fish Plants