So often I go to visit struggling reef aquariums and am faced with the same simple problems, such and incorrect positioning, inadequate supplements and incorrect water parameters.

It is important to understand the position that a particular coral grows in the wild. Corals grow to maximize the amount of light they are able to collect. I will often go to people’s house to find their corals are for the most part all facing forward, when they should be facing up so the beautiful colours of the coral can be enjoyed by the aquarist from the front. The reality of this is that the coral is not likely to survive for an extended period of time. In the wild the light would have come from directly over the top of it, whereas now the light may be coming from one side. When this is the case, you will see the polyps on the far side start to recede and die with time, often causing a bacterial infection, which may claim the remainder of the coral.

When positioning a coral, remember that the face of the coral is naturally meant to be facing up, so it pays to have an amount of live rock built up towards the back allowing you to position the corals on a 45 degree angle. The most important consideration is to ensure that the whole surface of the coral is being exposed to the light; the second consideration is trying to position it to allow it to be enjoyed from the front. Due to this reason people don’t tend to position their reef aquarium too high on a stand as viewing the tank from a lower position will always display the corals to their best advantage.

A coral must be positioned according to its requirement for light and waterflow. Corals with higher demands for light and flow should be placed at the top of the aquarium. Corals with lower demands can be placed deeper in the aquarium. Knowing if a new species you wish to keep is a shallow, medium or deep water species to start with is a very good idea. Aim to position the coral according to your understanding of its light demands then watch how it reacts. Determining the corals water flow requirements is somewhat easier. Assuming you have at least 14 times per hour water flow and you see the coral struggling to open with the force of the flow then you can presume it is too strong so simply move the coral away from the pump outlet. Alternatively, if you see mucus gathering over the coral which is not being swept away and the coral is not waving nicely when it is extended then you may decide that it is not in enough flow. If this is the case simply move it towards a pump outlet.

You must be watching all the time for corals stinging each other. Not only must their be a gap between each coral when they are fully extended, you must also be aware of sweeper tentacles which will appear at night full of stinging cells trying to suppress their competition. Be careful which coral is upstream to the next and always try to position the more aggressive species downstream. An aggressive coral upstream to a peaceful one is a major risk but it is possible to exchange their positions and therefore keep the weaker animal out of harms way. It is worth viewing your aquarium at night and pay attention to the sweeper tentacles and the effect they may have on their neighbours over time.

Understanding how to group corals can be very handy because some corals will sting each other while others will not. Mostly corals of the same genus are safe to put together. These animals are safely grouped and can create an amazing feature. Having one area for soft corals, one for stony corals and another for small polyp corals will add to the dynamics of the tank and is an excellent idea.

No tank can grow all species all the time because corals are always at war with each other using chemicals and shadowing to dominate others. Not only do the corals physically sting each other but they also release chemicals into the water which will affect other coral. I have found that aquariums that have a lot of one particular coral thriving are not able to grow various other types. These observations should be noted because if you repeatedly try a species and it just doesn’t seem to work even though in the past it has thrived in that same condition, it could well be the chemical war. Water changes, protein skimming and chemical media such as activated carbon like Biochem-Zorb will help lessen the effects of coral chemical wars.

Corals in aquariums I visit often suffer from bacterial infections. These infections appear as a milky haze on the animal. This is mostly caused by low immune systems, low waterflow, inadequate vitamins and trace elements or harassment from fish or other corals. Firstly ascertain the cause of the infection, eliminate that problem then treat the coral ASAP. Firstly, remove the coral and brush off the infection and give it a 10 minute freshwater bath containing an iodide solution. If the infection continues despite several attempts, cut off the affected area leaving only healthy tissue. This is harmless to the animal and may well save its life. Ensure that your iodide level is maintained at 0.06ppm, especially if you are experiencing bacterial infections as iodide will help to control these and increase the immune system of the coral.

Sedimentation is mostly overlooked by aquarists. This is particularly a problem with very porous species of coral. This is easy to find which species suffer from sedimentation by simply waving your hand over it or picking up the specimen and shaking it in the water. Surprisingly, a shower of sediment will often fall out of the structure of the animal. This sediment is a problem because it quickly becomes anaerobic, slowly leaking hydrogen sulfide gas out over the coral. These animals suffering from sedimentation will start to recede and eventually die. Sedimentation can also be an issue with other corals in aquariums without mechanical filters or adequate waterflow, where the sediment is able to gather on the surface of the coral.

Many reef aquariums will never reach their potential due to something as simple as one pestering nippy fish. Many fish will nip at the coral causing it to close, this simple act may appear harmless but repetitively through out the day it can be enough to reduce the life of the animal. Many people make excuses for their beloved favourite fish and are blind to the fact that it is slowly killing some of the corals. Many fish behave differently when you are present in the room, so it is a good idea to hide from the view of the fish and watch how they behave when you are not around. Other people are aware of the problem but are not prepared to go to the effort required to remove the fish because they can’t catch it. If you want to have a thriving reef tank you must be ready to do what it takes to remove fish that prove to be a problem, even if this requires removing all the rocks and coral.

It is common for people to house sand Gobies in their aquarium. While this is a great way to ensure you have clean sand, it can be detrimental to many types of coral as the Gobies will pick up sand and swim through the tank dumping sand all over the coral. Some types of coral are affected by this action and may perish due to it. If you do have Gobies watch for this problem and be wary which corals you place towards the bottom of the tank.

Old tank syndrome is a phenomenon suffered by many aquariums, particularly those with high fish loads, no mechanical filter or thick sand beds. Old tank syndrome is where the aquarium seems to have deteriorated over time even though you are looking after it as well as ever and your water parameters still seem to test as good. When this is occurring, the tank may need a spring clean. To give the tank a spring clean, perform a large water change, clean all the filters and rearrange the rocks in the back of the aquarium allowing you access with a gravel siphon. It many take several attempts to allow the aquarium to return to its former glory.

Old tank syndrome is often caused by the build up of sediment and detritus at the back of the tank. In this sediment, hydrogen sulfide can be created, leeching into the aquarium and lowering the immune system of the fish and corals.

Incorrect parameters are too often tolerated by even keen hobbyists. It is important to remember that if the water is not quite right then with time the aquarium will be not quite right. Even low levels of nitrate and phosphate will have a cost if given enough time. Many animals can survive in water which is not quite right but what they are doing is exactly that, surviving. Isn’t our aim to have aquariums that thrive? I suggest deciding on the quality of water that you wish to aim for and really strive to maintain it. Don’t become complacent because it looks ok now. Things like low levels of phosphate or slightly high temperatures may not have an immediate effect but will have a cost over time. The affect of this tends to be one coral at a time slowly dies off even though most of the others still look fantastic. If it’s not right, then it`s not right.

Time and time again I find the difference between an aquarium that survives and one that thrives is in the level of magnesium. Most people are aware of magnesium and do add it on a weekly basis but few ever get the level to the required 1200ppm. Weekly additions are advisable but they tend only to help maintain the magnesium level. I have found that much larger doses are required initially in order to get the magnesium level up in the first place. Once the level is maintained I so often find the whole aquarium really starts to thrive and the corals and coralline algae really start to grow. Magnesium is an essential element for corals and it will allow your calcium, pH and kH levels to stay in solution as it acts as a bonding agent.

Good luck and enjoy.
Paul Talbot