Hey fellow saltwater aquarium fans!
Yes its true coral keeping can be challenging, but once you get those babies thriving your aquarium will look magnificent and you will be the envy of all your friends. If you focus on 4 major parameters and get them optimised for your coral you give yourself the best chance of success.
The care requirements of coral become obvious when you become a science geek like me and think about the environment in which they naturally occur: the nutrient free, constantly moving, stable tropical ocean with its intense natural sunlight. And thats what we need to recreate in our homes.
These are the 4 vital ingredients for keeping thriving corals;
1. Consistant, pristine water quality:
This means stable temperature, pH and high alkalinity with (ideally) undetectable levels of nitrate and phosphate. This can be easy to achieve by using a really good quality filtered water source such as RO (reverse osmosis) purified water.
Using a protein skimmer will keep the water super clean and oxygenised by removing dissolved organic waste before it is mineralised into deadly ammonia. As ive said before protein skimmers really help and I consider them a must for reef aquariums to make your life easier 🙂
Regular partial water changes will get rid of excess nitrates and phosphates and replenish vital trace elements (so you need to use less of the overrrated and often overused supplements), they will also add buffering capacity back to the water making it more resistant to pH shifts and chemical imbalances.
2. Vigorous, multi-directional water movement:
Coral reefs are always turbulent, swift flowing environments; the currents rinse debris and mucus from the corals, oxygenate them and bring them their supplementary protein packed plankton food. This is what corals like and if we dont provide them this they will die.Even marine fish do better with higher water flow.
A couple of big powerheads mounted in the corners with their flows aimed at each other is a good way of doing this, we want water flowing in every direction with no dead spots in the tank. Using a few stratigically placed big powerheads is better than many smaller ones, which will create more heat. Be careful corals arent placed in the direct path of thhe powerheads output; this can easily kill them (too much of a good thing!).
3. Intense lighting of the correct quality and duration:
Mimicking the tropical suns rays is a must for healthy photosynthesizing corals, having a regular 10-12 hour rhythm with a dawn and dust period (actinic light only) are ideal. Also using full spectrum bulbs with the right colour temperature for the corals you wish to keep is a must. For general reef applications this means less than 12000K, deep water species are harder to keep and need 12000K+. The choices of different lighting platforms and set-ups are mind-boggling (see my reef lighting article for more information) T5’s, power compacts are perfect for most corals, LPS corals however will prefer metal halide’s supernova-like light intensity.
4. Supplementary feeding and the correct trace elements:
If you think that photosynthetic corals get all their food from the sun (autotropic), then think again, the majority of corals are heterotrophic (meaning they photosynthesise and also catch their food) so feed on plankton at night when the lights go out, this is why coral polyps look like tiny anemones to catch their protein loaded food!
Corals that contain photosynthesising zooanthelae in their tissues (the symbiotic algae cells that harvest energy from sunlight) actually get anywhere from 20-50% of their total energy requirements from feeding off plankton and most hard corals can get all of their energy from planktonic filter feeding. Supplementary feeding with zooplankton will make your corals do even better.
Trace elements such as calcium (ideally 420 ppm), strontium (ideally 8ppm), iron (ideally 0.05 ppm) and magensium (ideally 1280 ppm) that cant be replenished by regular partial water changes ( iron and often strontium can) will need to be regularly dosed and monitored to have an optimally growing reef.
If you are concious of and adhere to my 4 vital ingredients for thriving corals you simply cant go wrong. This is all corals really need to do fantastically well in your saltwater aquarium, everything else is just hype!