Using an LED light fixture

Following many requests for explanations, I decided to look more closely at this subject, fully aware that I lack the technical expertise to discuss PAR, lux, let alone wavelengths. In any case, since I was one of the first to fit LED fixtures to my tank (specifically the Ecotech Marine Radion G2 Pro, G3 Pro and finally G4 Pro), I assume that over this time I have gained the necessary experience, which I would like to share with all the friends of BallingMania.

Everything changes from one fixture to another

That said, I believe that from one fixture to another anything and everything can change: the type and power of the LEDs and their number for the same coverage vary significantly; these fixtures also differ in their optics (different beam angles), or may even have none at all.

As for PAR, lux and wavelengths, many reefkeepers believe that to assess an LED fixture you need a PAR meter; personally I am firmly convinced that to find out whether these fixtures work or not, they must be tested (for about three months) on the aquarium to check their effects: this way we will be able to judge how effective they are and what impact they have on the animals kept.

I would like to point out that:

• What I say is not the absolute truth, but describes my personal experience from constant use of Ecotech Marine Radion LED fixtures, the X30 type.
• Easy LED fixtures and bars are a step below T5s, but I am referring to the animals' well-being, not to their colours.
• My personal considerations and assessments relate strictly to keeping stony corals (SPS and LPS).

LEDs or T5s: what suits a beginner

In view of the above, I think that running a tank with LED lighting is slightly more complicated than one with a T5 fixture, because changes (see the Triad and phosphate levels) are quite rapid, so you need a sharp eye to read these changes in good time. So, logically, I should advise beginners to use T5 fixtures, since they are easier to manage, but that is not the case.

My suggestion is to use LED fixtures, keeping soft corals at first; only later (after gaining the necessary management experience) can you start adding some easy stony corals to the tank, such as foliose and digitate Montipora. In any case, it must be said that a mid-range LED fixture costs quite a lot, so if your budget is fairly limited I strongly recommend buying a T5 fluorescent fixture; but please also consider that, if you absolutely need to cut your electricity bill, an LED fixture reduces costs by about 30% compared with a traditional fluorescent one.

The controller and the channels

Another thing to consider when choosing an LED fixture is whether it has a controller that lets you change the power of the individual LED channels (white, blue, royal blue, red, green, indigo and UV); the beginner will want to avoid constantly fiddling with them in a desperate search for the perfect combination, otherwise the animals in the tank get stressed and in some cases die.

1. 1LEDs type, power and number change from fixture to fixture
2. 2Optics different beam angles, or no optics at all
3. 3Controller sets the power of each channel
4. 4Animals get stressed if you keep changing

Channels can be set one by one, but the beginner will want to avoid fiddling in search of the perfect combination.

Reading the tank

I would like to point out that if you buy an LED fixture, there is no mathematical certainty about how and when you will have to feed more or less, or vice versa; the same goes for dosing trace elements and managing the Triad: KH, Ca and Mg. For these reasons, do not automatically increase doses when you switch from a T5 fixture to an LED one.

I repeat: you must read the state of your tank to understand when it becomes counterproductive to increase feeding and add trace elements (for example a nutrient-rich tank with dark animals), and when instead you should feed and add trace elements, when your animals show good polyp extension and their colours are fairly light. These particular aspects can be confirmed by testing NO3 and PO4, which in this case should be close to zero.

1. 1Dark animals rich tank: more food and trace elements are counterproductive
2. 2Fairly light colours here you can feed and supplement
3. 3Polyps extended good extension: the other sign to look for
4. 4Tests the values that confirm what you see

Do not increase automatically: colour, polyps and tests decide.

I realise the matter is fairly complicated, but my aim is to make you understand how important it is to learn to read the state of your own tank and to change your management promptly according to how things develop.

Four tips

Finally, as a general rule, I would like to share the following tips:

1. If you buy an LED fixture to replace another type of lighting, you need to rescale the LED power at first, setting low percentages for the individual channels and for overall power, then increase them gradually by 5% every seven days.
2. The minimum height of the LED fixture above the water surface should not be less than 25 cm;
3. New additions should be acclimatised by placing them on the bottom of the tank, and after seven days you can move the coral to the desired spot on the rockwork, but please take into account the specific needs of the animal in question.
4. The key to success does not depend only on using LEDs or T5 fluorescents but on a series of factors, such as how the Triad is managed, the type of skimmer, the sump design, adequate exchange between tank and sump, and, no less important, the circulation pumps.

1. 1Low start low percentages for each channel and for overall power
2. 2A 5% step the increase is gradual
3. 3Every seven days only one step a week

The steps show the pace, not the values: the text does not say which percentage to start from.

1. 1LED fixture hanging above the tank
2. 2Minimum height above the water surface: no less than 25 cm
3. 3On the bottom the new coral acclimatises here
4. 4In the desired spot after seven days, according to the animal's needs

The new arrival starts on the bottom and moves up to the rockwork only after a week.

1. 1Light LEDs or T5 tubes
2. 2Circulation pumps no less important than the rest
3. 3Tank/sump exchange must be adequate
4. 4Skimmer the type matters
5. 5Sump design not a minor detail
6. 6Triad management the chosen method matters

Success does not depend only on LEDs or T5 tubes, but on the whole system.

author: Ciro Murino

Sources

1. Rosset S., Wiedenmann J., Reed A.J., D'Angelo C. (2017). Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates. Marine Pollution Bulletin 118: 180-187.
2. Wijgerde T., van Melis A., Silva C.I.F., Leal M.C. et al. (2014). Red Light Represses the Photophysiology of the Scleractinian Coral Stylophora pistillata. PLoS ONE 9: e92781.
3. Wijgerde T., Henkemans P., Osinga R. (2012). Effects of irradiance and light spectrum on growth of the scleractinian coral Galaxea fascicularis: Applicability of LEP and LED lighting to coral aquaculture. Aquaculture 344-349: 188-193.
4. Langlois L.A., Hoogenboom M.O. (2014). Capacity for short-term physiological acclimation to light does not control the lower depth distributions of branching corals. Marine Ecology Progress Series 508: 149-162.