Aquascaping a marine tank is slightly different to that of a freshwater aquarium. Jeremy explains how to build the foundations of your reef.
Over the last few articles in this beginner reefkeeping series, we’ve covered some of the essential pieces of equipment you need:
But how do you actually make the tank itself look good?
Well, laying out the décor can be one of the most fun parts of setting up a reef tank, and it allows you to bring your creativity to the forefront. At this stage there are two main aspects to aquascaping the tank: setting the rocks and then furnishing the bottom with a layer of sand.
Unlike decades gone by, when live rock had to be kept wet and placed into a pre-filled tank, the vast majority of reefs now use dry rock and aquascape it – arrange and place it – before the tank is filled with water. This has many advantages, as dry rock doesn’t contain any pests, but also means you can take as long as you want to arrange the rock, even several weeks if you want to, to get the layout just right.
Aiptasia is a common pest found on live rock - Photo by Shutterstock
Related article: Marine Hitchhikers: Natural Pest Control for Reef Tanks.
Aquascaping with rock
When aquascaping with rock, two factors come into play – the way the water flows around the rocks and the way it looks.
A clean reef is a healthy reef, so we want the minimum amount of rock touching the tank base, so that detritus can’t build up out of sight. We also want to be able to get gravel syphons, scrapers and algae magnets around all sides of the rocks and corals to keep it clean on an ongoing basis.
Start with some flat-bottomed rocks that will form the feet of the aquascape. Bring them away from the back glass by at least two inches so water can flow around them. Then use other plate and branch shapes to create archways, caves and platforms to place corals, but also allow good water flow through them too.
Photo by ARKA BIOTECH
In art and aquascaping, the rule of two-thirds is used, whereby if you place an interesting rock two-thirds along the tank and two-thirds up, it will become a natural focal point and draw the eye. That’s also the place to put your favourite coral.
Related article: Carrying a torch for LPS corals.
Reefkeeping Top Tip
Rockscapes don’t even have to be created inside the tank. Instead, they can be mocked up and stuck together outside the tank to avoid the risk of scratches and rockfalls as you move the jagged rocks around. Create your tank’s footprint and height using masking tape or cardboard boxes and then you can create the whole aquascape outside the tank before carefully lifting it in.
Stick your reef rock together
Another important advance in reefkeeping is sticking rocks together. Strong water flow and top-heavy coral growth can cause rocks to slide, so use special reefing cement to stick the rock structures fast, so that they are solid when they go into the tank.
Reef cement is an excellent thing as it also enables gravity-defying archways and plates, which always give a really natural effect.
Place the rockwork away from the sides by at least 5 cm (2 in), and the front panel by at least 15 cm (6 in), as this will allow for coral growth while still giving access for regular maintenance.
The temptation will be to build rockwork right up to the top of the tank, but that may cause shading once the lights are on. And don’t forget that corals grow a living aquascape, adding 15–30 cm (6–12 in) of height on top of the rockwork once they’re grown in.
Pistol shrimp and goby pair emerging from a burrow - Photo by Shutterstock
Build the rockwork straight up off the tank base so that it's always stable, even if the sand shifts. Animals that like to dig, like pistol shrimps, can undermine the rocks, making them unstable otherwise.
Place plastic egg crate under large, heavy structures for extra peace of mind and to spread any pressure points on the tank glass.
Only choose rockwork from reef stores which has been selected specifically for the job. It won’t leach nitrates and phosphates and its limestone structure can help to buffer the pH and hardness of the water.
Use a two-part epoxy putty to stick coral bases to the rockwork so they are held fast too.
Green humphead parrotfish excreting a cloud of coral sand - Photo by Shutterstock
Sand for reefs
Coral reefs actually manufacture their own sand, as parrotfish crush up and consume coral skeletons and calcareous rocks and pass it out at the other end.
Coral sand completes the reef look with its fine, white granules, and it can aid cycling (if you buy live sand) and buffer the water too.
Coral sand and aragonite sand are different to builder’s sand or play sand as they are made from calcium carbonate – good for corals – and they don’t leach silicates, which cause algae.
Live sand comes packaged wet, and includes microbes, but it must only be added to full-strength seawater once the tank is filled and up to temperature.
Dry sand should be rinsed first with RO water to remove any dust and then placed in a thin layer around the rocks, covering the whole base of the tank.
Aim for a thickness of just 3 cm (1.2 in) deep unless you plan to stock a species that requires a deeper sand bed, such as some wrasses. Too deep and it will collect detritus, but go too shallow and bare glass can be exposed and look unnatural.
Ornate leopard wrasse - Photo by Shutterstock
Fine sand is more likely to be blown around in strong currents, so choose larger grains if water movement will be strong, as in an SPS dominated reef.
Some reefers don’t use substrate at all and run “bare bottom” tanks. Although not natural looking, it's one less thing to look after if striving for water parameter perfection. It also means you can have crazy strong flow without fear of the sand being blown around.
So, what are you waiting for! It is time to get your hands on some reef rocks and get creative!
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