There are many different types of marine reef systems functioning successfully throughout the world. Each system is different in its own way and many are geared towards keeping different species or achieving different goals. As a new hobbyist, you are most likely concerned with housing beautiful fish and invertebrate similar to what you might have seen in your local fish store, or maybe at a friend's home. What ever the reason, the beginning to setting up a successful system always starts the same way. And that is collecting information and doing research. I'm assuming that you are not interested in setting up a reef in your home, but a SUCCESSFUL reef in your home. Why else would you be on the internet scouring the web for information? I commend you at getting this far without rushing home with a bag of salt mix, an empty aquarium and your first specimen in it's plastic bag!
Some systems may be very basic, consisting of a couple of air stones and a container of seawater with a small amount of live rock. Others may be very complex with a downdraft skimmer, ozonizer, calcium reactor, metal halide lamps supplemented with other forms of lighting, a chiller and other equipment. Don't let any of this intimidate you. We will cover all of this equipment later on down the road. For now, lets look at what all systems have in common. The water chemistry.
The Nitrogen Cycle
In reef systems, water chemistry becomes far more of an importance than what you may be accustomed to. Every piece of food, every specimen placed in the system and yes, even the water itself have potential for degrading water quality. How do we address this? By understanding this cycle and knowing how to control it. There are many aquarists out there that maintain a somewhat successful system without understanding the nitrogen cycle by just doing what a book tells them to do or by doing weekly heavy water changes on their systems. But having this knowledge should be considered a must for any aquarist, especially one keeping sensitive invertebrates. Not only will this help ensure that your system remains in good condition, but it will ensure that your fish and invertebrates not only live, but thrive! It is not uncommon to see species of marine life in captivity doing as well as they would be in nature, but you know what? sometimes they can do even better! This is all up to you and I as hobbyists.
The nitrogen cycle can be a very complex subject. But it can also be easily understandable when we take a look at just what it is. Just what starts this cycle and where does it end?
Any marine organism, plant, aquarium food or supplement, and even bacteria that naturally occurs in our systems has the potential to undergo the nitrogen cycle. As these organics break down in our systems, much of what is created is used by other organisms and processes. The rest is converted to Ammonia (NH3). Ammonia is extremely toxic to both fish and invertebrates in very small amounts, therefore we must control it by limiting how much food we feed, how many specimen we add to our systems and by maintaining good biological, chemical and mechanical filtration (more on filtration later). In any case, ammonia will be produced in our systems but we can control limited amounts with little to no impact on our captive reefs.
As an bacteria metabolizes ammonia, it breaks down, and much of it is converted to Nitrite (NO2). Nitrite is much less toxic than ammonia but still a major problem in marine aquariums. Nitrite is then broken down by other bacteria into nitrates (NO3). Nitrate in turn is out-gassed through aeration and removed through frequent water changes and other processes.
In order for this process to be possible, we must allow our systems to develop adequate amounts of these necessary bacteria to carry the process out. This is why we can not immediately introduce organisms to our systems in the beginning. When our systems develop levels of beneficial bacteria and have gone through the initial nitrogen cycle, we can very slowly begin to add our specimens. Each time we had a new specimen, our systems must cope with this new load, producing more bacteria to handle the increase in organic load.
So what can one do to help this process along? There are bacteria cultures available at your local fish store that can be utilized for establishing your system, however these cultures don't always work. A better method you can utilize is by removing a small amount of sand or live rock from an existing system to seed your new system. Keep in mind that live rock and live sand purchased from your local fish store will already have these bacteria onboard though the rock and sand may go through an initial die-off making the wait inevitable.
Without getting too sophisticated, pH is basically a measurement of acidity or alkalinity in the reef aquarium. Ideally the PH level should be between 8.0 and 8.3, with an optimum level being at 8.2. The normal tendency is for the level to fall rather than rise, so PH levels should be monitored closely. Test kits to monitor pH are easily available at your local fish store. Additionally, meters are slowly becoming more available to electronically measure pH for you. They commonly start at around $50.00. (US) Small weekly additions of sodium bicarbonate (baking soda) help to buffer pH. I just about 1tsp per 20 gallons of system water (not total system capacity) per week when doing water changes.
Salinity is the amount of inorganic material (salts) dissolved in the seawater. Salinity is usually expressed as weight in grams per kilogram of seawater or parts per thousand. Usually salinity of seawater is about 33 - 35 g/Kg, although this value will increase with evaporation. Commonly as reef aquarists, we look at salinity in the form of specific gravity.
In my opinion, a common reef system should be maintained at a specific gravity between 1.023 and 1.026. Systems have been successfully maintained at lower levels than this, sometimes as low as 1.019, but in my experience, I find that many sensitive invertebrates do better at higher levels (1.026 being the extreme high end).
However, once again stability is the key. Find what works for you and strive to maintain it.
Utilizing a meter similar to the one pictured is probably your best bet to measure specific gravity unless you happen to have access to an electronic meter (slowly becoming more available throughout local fish stores..
Salinity is also effected by temperature and should be adjusted accordingly to obtain a correct result. This adjustment is minimal but for a correct reading, is required. The benchmark temperature is 60 degrees Fahrenheit. Here is a table that will help you adjust your salinity for temperatures over 60 degrees F.
A reef aquarium typically does well between temperatures of 74 and 80 degrees F. The key to maintaining correct temperature is stability. Even if your system runs slightly warmer than 80 degrees F., it's best to keep it in a stable environment. However, at temperatures exceeding 85 degrees F. we should become increasingly concerned.
There are many ways to keep our aquariums cool on hot days. Some of which are:
- removing any glass covers over the water's surface and utilizing a fan to blow across the surface for better evaporative cooling
- purchasing a chiller to keep aquarium cool
- keeping room cool by keeping window blinds and curtains shut on hot days
- utilizing an air-conditioner to keep both you and your aquarium cool
- turning on lights after the hottest period of the day has passed
- monitoring equipment for excessive heat production (internal equipment = HEAT)
The last of my suggestions deserves added attention as it is commonly the most overlooked form of heat transfer in the aquarium. I have seen on many occasions systems running high temperatures due to excessive equipment. For example, did you know that a single powerhead can add as much as 2 degrees to your systems temperature? Many aquarists run as many as 8 powerheads in an attempt to provide good current.
Is there a solution to this common problem? I'm glad you asked! It's as simple as utilizing an external pump instead of several powerheads for water circulation. If you already have an external pump but need additional water movement, it may be time to move up to a larger-capacity pump. All internal equipment should be limited as much as possible to reduce heat that is added to the system. This is VERY important in smaller systems.
Seawater & Salt Mixes
Basically, you are looking at two choices for a saltwater source. Natural seawater and synthetic salt mixes. There was a time when I would have said that no synthetic salt-mix can compare with natural seawater. I can still recall the countless trips I have made to the free, sand-filtered seawater station at Scripps Pier near my home in San Diego, my small car loaded with as much as 70 gallons of bottled seawater. I could barely drive my care up the steep hill that lead back to the main road! Fortunately for my car and hobbyists world-wide, times have changed and major advances in synthetic salt mixes have been achieved on a grand scale. Currently, there are several scientific-grade salt mixes available to the reef aquarist, which are commonly even more stable than natural seawater! (natural seawater has a tendency to degrade much faster than a good synthetic sea-salt mix)
The important thing to remember, when mixing synthetic seawater, know your source of make-up water. Oftentimes, tap-water can contain heavy phosphates, silicates, fluoride, and even copper which is deadly to marine invertebrates.
Recently, I read an article in my local paper about the city of Orange, CA. in an attempt to conserve dwindling groundwater supplies, switched to imported supplies from another water-source outside the city. The imported water contained heavy chloramines, which control contaminants but are deadly to marine and freshwater fish and invertebrates. The city informed local dialysis centers due to the impact that chloramines would have on dialysis patients, though no general notice was given. Many hobbyists lost their entire livestock.
Your water company is bound by law to give its customers a full analysis report of it's water upon demand. If you plan on using water from tap, this could definitely come in handy, even if you are planning on using a DI/RO unit.
Speaking of DI/RO units, it would be a good idea to purchase one if at all possible. These units will quickly pay for themselves in money they will save you from running to a public RO/DI source.
Follow the manufacturers directions for mixing salt-mix. Allow it time to sit and test its salinity prior to adding it to the main system when doing water changes. Newly prepared seawater tends to increase in salinity over the first couple of hours. If possible, allow mix to sit for a few days after preparation.
Phosphate is found naturally in the marine environment in small quantities and is actually utilized in biological processes of many marine organisms. However, high levels of phosphate are directly related to outbreaks of problematic algae as well as being an inhibiter of the calcification process. We should strive to maintain phosphate levels at or near undetectable levels at all times.
Some major sources of phosphates are:
- Water used for evaporation replacement or during water changes
- Heavy feedings or use of foods with heavy phosphate levels
Phosphate test kits can be used to determine levels of (PO4) in the system, however most test kits measure only inorganic phosphates. Additionally, phosphates that have bonded to rock and substrate (bottom matierial) are not detectable.
One must also realize that if phosphate is being utilized by problematic algae, a test kit may not report accurate results as the (PO4) is being utilized as rapidly as it is being added to the system.
Some controlling factors are:
- Utilizing granulated activated carbon that is phosphate free
- Heavy protein skimming (strong skimming effectively removes phosphates)
- Regular additions of kalkwasser (high calcium levels cause phosphate to fall out of solution)
- Additions of macro-algae to utilize phosphate
- Careful feedings
- Regular water changes with RO/DI water.