Buying a Marine Tank

Ideally nothing smaller than a 200L system, approximately 1 m 20cm by 45 cm by 45 cm. Once one has decided on the size of tank you must then decide on whether the tank is going to be fish only, or a reef tank, meaning corals anemones and fish. It is always advisable to start with a fish only tank until you are confidant with your water management skills. One must then look at the various options on lighting and what type of equipment you are going to need? The other important thing one must look at is whether to use live rock or ceramic rock. This decision plays a very important role in the success of a reef tank. As live rock is your main biological filter.

Other important decisions to be made are fish options in both fish only and reef aquaria, as there are certain fish that are not compatible with each other or in a reef tank due to incompatibility of invertebrates (corals, shrimps). This is when you need the help of a reliable pet store. What is most important here is finding a pet store that you trust, the easiest way to tell if a pet store is offering good advice is to inspect their display tanks if the tanks are healthy and thriving then the advice will be good and solid, based on systems that work. I recommend strongly sticking to one pet store until you have an idea of what you are doing.

The best investment in this hobby is knowledge, gained through reading books by recognized authors and starting off with a goal in mind. There are many different mythologies for maintaining a successful marine aquarium and may be very confusing at times.

Tank size.
As mentioned above 200 L is an ideal minimum size to start with. (But always go as big as you can with regards to space and budget)

Equipment.
The sump and other options.
One must decide whether you are going to have a tank with a sump (the sump is a tank underneath the main tank that holds the equipment), or whether you going to have a filter that will just clip onto the side of the tank (this option is only ideal for small tanks). This is a very important decision. Option one is almost a must in a reef tank as waste in sea water collects at the top of the water column and forms a film on the surface of the water which is clearly visible and can hinder oxygen diffusing into the water. When you have a sump in place the surface of the water is continually skimmed and the scum is fed to the filtration where it belongs. Another advantage of a sump is a lager volume of water which again adds more stability to a marine system.

Power heads.
Power heads are what we use to circulate the water in the tank. This plays an important role when you consider we are trying to simulate the movement of the sea. For a reef tank I recommend turning the volume of the tank over a minimum of 10 times an hour depending on what corals you are going to be keeping, and a fish only system anything from 4 times an hour.

Return pump.
This is the pump that returns the water from the sump back to the tank. The volume of this water turned over through the sump should be between 2 and 6 times an hour depending on whether it is fish only or a reef system. Generally we find a reef system requiring less turnover through the sump, (between 2 and 4 times) fish only, requiring more (between 4 and 6 times).

Protein skimmer.
This is the most important piece of equipment in the tank. Look at it as the heart of the system as it is your primary source of waste removal. What a protein skimmer does is remove all the excess waste out of the water, which is caused by fish waste and decaying matter. As you can imagine with out a protein skimmer all the excess nutrient builds up in the tank causing problems with your water quality, and in turn stressing the inhabitants resulting in sick fish or dying coral. Try not to buy the cheapest model you can lay your hands on! If you speak to any experienced, successful aquarist they will agree that this is one piece of equipment where you can’t cut corners.

How does a protein skimmer work?
In simple terms, it is the mixing of air and water, if you have ever been to the beach on a windy day and seen the brown foam that collects on top of the water, this is exactly what a skimmer does, and then allows easy removal of the waste collected in a cup on the top of the skimmer. There are many types and styles of skimmers, at the end of the day the efficiency of a skimmer is judged by how much waste it can remove from a system and one of the main factors here is contact time between air and water. What happens is the waste particle sticks to the air bubble and rises to the top of the skimmer and is expelled into the cup and clean water exits from the skimmer. Although it sounds fairly simple the actual chemistry of this process is fairly complex. The new age skimmers all use needle wheel or venturie technology to provide air to the skimmer, these methods allow for a fine and high bubble flow rate.

Heating and chilling. (Temperature)
Don’t buy anything too cheap as temperature stability plays an important role. Fish don’t like more than 2° variants. This is always a problem in our climate as our summers are very hot and keeping the tanks at approximately 25°C is a problem (use computer fans to keep cool). Where as in winter buying a reliable heater can easily keep your tank at a constant 25 Celsius.

Biological filtration.
A biological filter is only needed in the advent of running a fish only system and should be avoided in a reef system where live rock should be your primary biological filter. The reason being the lighting used in a reef aquarium could cause algae problems as bio filter media produce more nitrate than a system can break down. In a fish only aquarium this is not as important as algae control is far easier. It is evident from this that you should not overstock a reef tank with fish. For a fish only system a compartment can be built into the sump which we put bio-balls into. The bio balls are a plastic ball to which the bacteria live on to help break down any excess waste. There are other mediums that one can use are course coral pieces, hair curlers and any other medium that bacteria will grow on. When making this decision as to which media to use, remember the product with the greatest surface area. The reason being the greater the surface area the more efficient due to larger amounts of bacteria.

Live Rock.
As mentioned before live rock plays a very real part in the success of a reef tank. The reason being it helps to create more of a living ecosystem (more stable environment). The live rock is a filter on its own and in turn helps to get rid of fish waste as well as any decaying matter. With in the live rock there are various types of worms as well as different types of bacteria that help keep the reef tank running more stable. If one uses live rock as their reef, you then do not have two worry about running a biological filter.

Coral Sand.
There are two options. Coral sand versus aragonite.
Coral sand being coral pieces crushed to make coral sand in various gauges. Advantages and disadvantages. Advantages of coral sand are being much cheaper. The disadvantage is being full of phosphates and does tend to become a detritus trap. Aragonite in my opinion only has pros. No phosphates and its sugar grain size so detritus is left on the top of the sand bed for easy removal. Ideal for a wrasse and small gobies. The only disadvantage is that it is slightly more expensive than coral sand.

Lighting.
A very debatable topic.
First question to ask yourself is, reef tank or fish tank. If reef tank one must consider we are trying to simulate the sun. This means in a simple form we can never give too much light, in the right spectrum for the right type of corals. For arguments sake one can keep most soft corals with far less light than all the hard corals that require very intense light. This decision must be made when taking into consideration the type of corals you are going to buy. Once again build a raport with your pet store.

What I recommend.
T5 is now the latest in technology as far as fluorescent lights go. We are achieving unbelievable results with these lights. They are driven with electronic ballasts so no starters are required. The other great thing is they last for approximately 3 years with virtually no loss of light intensity (Kelvin rating). We find these lights work in tanks well up to 60 cm deep.

Metal Halide.
Metal halides are generally used in deep tanks anything over 60 cm or in aquariums that require very intense light due to the corals that are being kept. These are generally used for hard corals and large tanks. What one can also do is run T5 in conjunction with metal halides in a large tank to create a more balanced light. Creating a sunrise and sunset for the corals. This is done by putting the T5 on a separate timer to the metal halides. Turn the T5 on first, two hours later metal halides for approximately 6 hours, and then T5′s for a further four hours.

If one sticks to what has been discussed above you should be off to a very good start in the hobby.