Reef & River Aquatics Home

Reef Tanks are definitely the way I want to go,
so where to from here??

The first question that you need to ask yourself is whether or not you want to keep corals, or wether you would be happiest with just fish and a few other non light requiring invertebrates like starfish, snails and shrimps.

The keeping of corals in captivity requires an approach that varies from the keeping of Fish – Only tanks, and can be quite a deal more costly than keeping fish only. We will deal specifically with Reef style tanks in this care sheet.

A minimum tank size to do a reef tank would be around 120 litres or more, with a tank that is deeper front to back than the average will make it easier to fit the required lighting, and gives an ability to build a good reef shape. The reason we don’t suggest doing reef in smaller tanks is a question of stability, i.e. the larger volume of water in a bigger tank will give you more time to react to a problem if one occurs.

The three major key requirements for a successful reef tank are :

1: Good Lighting. Corals are photosynthetic the same as plants and derive a large portion of the energy that they use to live, through the light that they absorb. If you are going to use fluorescent lighting, the absolute bare minimum is two full length flouro tubes, with 3, 4 or even 5 tubes being more appropriate. Flouro tubes need to be replaced every six to nine months, and can therefore work out to be a bit expensive in the long run. Metal Halide lights are a more expensive unit to purchase initially, but the corals benefit greatly from the use of this type of lighting, and because the bulbs only need to be replaced every eighteen months, halides are by far the better choice long term.

2: Good Water Flow. Corals rely on the movement of water over their bodies to remove waste products away from themselves. (unlike more muscular & mobile animals they cannot expel their waste very far nor can they walk away from it) This means that you need to include a number of water circulating pumps in the design of your aquarium. These produce both the rippling of the surface water that allows good gas exchange, and it also produces the movement that you see from the corals in a reef tank. As a general rule the more water movement the better, so don’t skimp on the powerheads…

3: Low Dissolved Organics. Corals live in areas that have very low levels of available nutrients and it is essential to recreate that as far as possible in the home aquarium. Feeding of the fish is one of the biggest inputs of nutrients into a tank, so this needs to be fairly tightly controlled. A lower number of fish in the tank means a lower amount of nutrient that needs to be added, so it is important not to plan on having too many fish in a reef tank and also to try to choose fish which will recycle nutrients that are already present in the tank wherever possible. It is also important to limit or eliminate the amount of tap water that goes into the tank as our tap water contains a lot of nutrients. (purified water is available from the store) Removal of organic matter can be achieved with the use of a good protein skimmer, and the best skimmer that you can afford should be included into the design of your aquarium. Skimmers range in price from around $100 through to around $600.

4: Trace Element Supplementation. Corals take elements out of the water to build up their skeletons and to support their bodily processes. These need to be replenished in the water. This is quite easy to do these days with a large range of supplements on the market for this purpose. We use and recommend the "Seachem" range of products as we have found them to be quite economical and also very easy to use.

There are different approaches to doing reef tanks, just the same as there are different approaches to doing most things in life. The approach that we use is to try and keep the aquarium running on as natural a basis as possible. We use deep sand beds or "plenum chambers" to help reduce nitrates in the water and we rely solely on the live rock to process the nitrogen breakdown cycle, as this is what occurs out there on the reef.

Unfortunately most of us are not in a position to do a few million litres of water changes a day like what happens out in the oceans, so we do have to be a bit careful about the fish we select for our tanks, and the amount of nutrients that are added to the tank on a regular basis. Water changes help to reduce nutrient build up and also replace some of the trace elements that are used up by the corals. As a guide around 10 – 20 % water change each fortnight should be a good level of water changing in a reef.

So now that we have covered the basic requirements of corals, how do we go about constructing a Reef Tank?

Firstly decide if you want to have all the equipment inside the tank, or wether you want to put a sump below the tank in a cabinet. A sump will add to the overall cost of the Reef, but it does allow you to remove a lot of the unsightly equipment down into the cabinet out of sight.

Secondly decide on the tank, you may already have a tank in which case your decision is already made, but if you are starting from scratch, we would recommend a tank that is at least 450mm from front to back, as this makes building a reef a lot easier. If the tank is to have a sump below it then the tank needs to be drilled so that the water can be drained away from it in a controlled manner. We can drill and supply plumbing fittings to suit this purpose.

Now that you have your tank & sump (or tank on its own) lay down either a structured layer system or just lay down a 3 – 4 inch bed of coral sand or marble sand (see "The Plenum Explained" caresheet for more info) Fill the tank with saltwater, and mount all the powerheads etc that are going to be included in the tank. Start up the protein skimmer and heater and allow the tank to circulate for at least a day to ensure everything is o.k. If all is well at this point then test the p.H. of the water and also the salinity. If all is well, and the tank is on temperature, then you are ready to begin adding live rock.

The addition of live rock should be done in a way that minimises the surface area of the sand bed that is covered (putting your base rocks on their edge rather than flat on the sand) . Live rock should be included at about the rate of around 10 kg or so for every forty litres of water in the system. (More is good) Build the rockwork up in a way that leaves lots of shelves and nooks and crannies so that you can use these spaces for the placement of corals later on. Don’t worry if looks "gappy" at the start, you will soon find yourself cursing if you haven’t left enough holes……

Run the lights for no more than two to three hours per day at this stage.

The tank should be left like this for around two to three weeks to ensure that the bacterial processes are fully underway. Testing of this is quite simple and can be performed at home very easily or we provide testing services in – store.

Once the Nitrogen cycle is complete it is time to begin introducing a few herbivores, (snails urchins etc.)

and fish (preferably herbivores too at this stage.) Lighting remains minimal at this point while your fist one or two fish settle in.

Two weeks or so later, the tank is ready for the introduction of a couple of corals, and the lighting period begins to be increased to around 6 – 7 hours per day. You are now at a point where you can begin to add corals in earnest, and as the number of corals grows, bring the lighting up gradually to it’s full time of around 10 hours per day. It is important that during the first three months or so that you do not add more than one or two fish per fortnight until you reach your maximum.

There you go, you are up & away with your Reef Tank.

We deal with the set up options for keeping "Fish Only" tanks in a different care sheet.