If you are setting up a saltwater tank one of your first considerations should be a protein skimmer. For fish only or reef tanks a good protein skimmer is vital to maintain the best possible water quality. The goal of a saltwater aquarium (and all of that equipment) is to recreate the beneficial aspects of the ocean. Your aquarium unlike the ocean is a closed system which without intervention will quickly accumulate unwanted levels of pollutants unless they are exported mechanically or biologically. There are a few different ways that those pollutants can be removed.
1. Water Changes- This is the most fundamental method of nutrient export. By replacing water on a regular basis with clean water nitrates, phosphates and other potentially problem elements are removed. My recommendation is to do a 10% water change each week. This is not only easier on your animals, but it is also easier for you. You won’t have to mix up as many gallons of water as you would with a once a month change, and you also will stay on top of other maintenance because you will be watching your tank more closely (salinity, calcium, temperature and cleaning protein skimmers and other equipment). Remember, the most important thing you can do for your tank is to maintain stability. If you wait to change your water once a month the balance in your tank will have more time to fluctuate and destabilize your tank.
2. Beneficial Bacteria- One of the reasons for starting a tank with live rock is to introduce beneficial bacteria that aid in the breakdown of those nutrients. When you feed your fish you are introducing nutrients into the system. Then the food is broken down further and expelled back into the tank. Next hermit crabs, other fish and dozens of other creatures, amphipods, copepods, worms, and your corals use what they can from that food source. At this point the nitrogen cycle is in full swing. The broken down fish food and waste is being converted into ammonium or ammonia which is then oxidized by bacteria called nitrosomonas. The byproduct of ammonia oxidation is nitrites which are then converted by another bacteria called nitrobacter into nitrates. Usually high levels of ammonia don’t occur in well established tanks, but in new tanks it is common to see spikes. However, even in well established tanks the death of a large fish or overfeeding for example can unwanted spikes in ammonia and ultimately nitrates which are harmful to corals.
4. Algae- Is extremely efficient at reducing phosphates and nitrates in your tank. By growing algae in a refugium or in the main tank you can greatly reduce the build up of phosphates and nitrates by continually removing algae as it grows. In this manner you are taking the algae which is now storing the phosphates and nitrates and your are removing them from the system. Hair algae outbreaks are often treated with animals which consume algae, however this doesn’t fight the cause of the algae. As those animals consume the algae they are unlocking what the algae has absorbed and placing it right back into the tank. Methods have to be taken to reduce the amount of nutrients added to the system in order to control the algae problem. Some of the most effective ways are to feed your fish slower to make sure no food is wasted, cut back on feedings to encourage your fish to eat some of the algae, rinse frozen food to get rid of the very fine particles of food that fish wont consume, increase the volume of your water changes, and use a higher powered or additional protein skimmer.
5. Anaerobic bacteria- Are useful in the process of removing nitrates from the tank (denitrification). Anaerobic bacteria live where oxygen isn’t present and convert nitrates to nitrogen gas which leaves your aquarium. These bacteria live deep within your live rock as well as in deep sand beds. I have read many conflicting views on how effective this process is. I personally think 3 to 5 inches of substrate will give you the benefit of not only anaerobic bacteria but worms and other creatures that naturally thrive in a deeper sand bed. Also, if you are planning to have Jawfish of any sort it is better for them if they have a deeper sand bed. Remember you don’t want to disturb your sand bed when siphoning water out for a change beyond the surface layer. Doing so disturbs the aerobic and anaerobic layers which are helping maintain your healthy aquarium.
6. Protein Skimming- The beauty of protein skimming is that you are removing the nutrients before they begin moving through the nitrogen cycle so they don’t have a chance to build up in the tank. This of this as your first line of defense, if you can get those nutrients out of the tank before they have anytime to being converting into nitrates the better off you will be. I always use a slightly over powered protein skimmer and leave it running all the time. Make sure you clean the collection cup out often to keep it running at an optimal level. Protein skimmers are also very effective at mixing oxygen into your aquarium water which alleviates the need to have a bubbling treasure chest (please don’t). Remember the next time you go to the beach that foam you are playing in is natures protein skimmer in action.
Don’t feel bad I played in it too.