Increasingly popular with hobbyists, marine nanos are the cheapest way to get into and start keeping corals.
What you will need
Tank: If you want tiny fish in some 40 l/ 8.8 gal of water this approach is recommended, though with inverts only you can go to 25 l/5.5 gal and under.
Expect to pay around £50 for a nano tank, including light.
Lighting: Most nanos already come with a light, but few will have one powerful enough for corals. Your best option is an upgrade, meaning either multiple compact fluorescents on an open-topped tank or a bright, powerful, compact LED.
Expect to pay £20 for small, compact fluorescent lights and up to £200 for a decent compact LED set-up.
Pumps: Filters are often supplied in nano tanks, so check the pump output rated on the side of the filter. A marine tank needs a minimum flow of ten times the tank volume per hour, so 400 lph for a 40 l/8.8 gal tank.
If any less you may need a small powerhead or circulation pump to boost your water flow.
Expect to pay £20 for a small circulation pump.
Live rock: Every reef tank should have live rock, regardless of size. As little as a kilo of live rock will make a huge difference to the ecosystem of a nano reef, introducing bacteria and other microscopic life.
Expect to pay £12.50 per kilo.
Sand: A thin layer of coral sand is all you need but, if you can afford it, opt for a layer of sugar-sized aragonite sand which may also help reduce nitrates.
Expect to pay £3.50 for 2.5 kilos of coral sand or £25 for aragonite.
Extras: These include salt and a hydrometer or refractometer. You’ll also need a thermometer, RO water to mix the salt with and saltwater test kits.
Expect to pay £60 upwards for these basics.
Corals: Soft corals are best for small and new tanks as they are the most hardy. Polyp colonies can easily be managed too and won’t outgrow the tank.
Expect to pay £50 for a selection of soft coral frags.