Taking the mayhem out of marine fish keeping
The Marine Tank Environment
Lighting your marine tank
You could quite easily fill a website like this just on marine lighting. There are so many different types and combinations to choose from and so many different opinions out there as to which ones will serve you the best that this page will very simply touch on the surface of the subject of marine lighting.
First and foremost having considered everything on the 'Starting your new Marine tank' page what are you keeping? If you are going for FOWLR because you have limited resources then the only thing you need lights for is so the fish know when to wake up and when to go to bed, and of course it also helps you to see them.
If you decide you want some corals then they will need a higher level of light to survive. Corals are an interesting combination of plant an animal. Everyone is familiar with the fact that plants need sunlight to survive, well corals are no different. The animals that make up a coral colony hold within them algae (a plant). The algae takes energy from the sun and converts this to sugars which the coral animal can use.
Different corals require different light levels to thrive so you will need to consider the pros and cons of each type of lighting if your still undecided on which corals you want to keep
There are many different types of flourescent lighting and again they type of coral you decide to keep will influence your final decision on what to use. A simple tank (and remember this whole website is about fish keeping on a tight budget) will often come with lights built into the lid. It the tank is intended to be a fresh water tank the lights may be T8' bulbs. These are the fat flourescent tubes you will be familiar with in shops and offices, (although the bulb output is different)
T8's don't cost the earth to run and if you are considering a nice, simple FOWLR they will suit you fine. Most tanks come with fittings for two lights in which case you would probably just use a 'marine white' and a 'marine blue' or 'actinic'
.As far as a FOWLR goes the blue will make colours stand out more and the tank will look more pleasing to the eye. Indeed if yu are keeping a FOWLR chances are your parameters will be less than perfect (fish have a higher tolerance to higher nitrate and phosphate levels than corals) and the last thing you want is super bright lights that will encourage the growth of unsightly algae.
There are even a few limited corals you can keep under T8 flourescent lights, I have kept simple soft corals like pulsing coral, kenya trees and a few zoas.
If, however, you have decided to go down the coral route then you need to consider your lighting more thoughtfully, if you read about marine aquarium lighting you will see 'approximately 1 watt per liter of water' banded about a lot. As a very general rule of thumb you can start of with this but as you read more into aquarium lighting you will realise it is only a very general guide.
There is a different flourescent tube available called a T5, these have become very popular and are often fitted as standard in new fish tanks. The tube is slimmer and the intensity of the light is brighter. If you use an original lid on your tank and it has a couple of T5 light fittings you will be able to consider many more soft corals. I have kept a nice, clean and thriving soft coral tank under two T5's with no problem (Toadstools, mushrooms, kenya trees, pulsing coral, zoas, cabbage corals for example). I daresay had I have had more than two bulbs the growth of these corals may have been quicker but they grew enough for me to frag them and swap them on.
You can keep almost every coral under T5 lighting, the factor is how many bulbs you run, you can get fittings that stand over the tank (or hang from the ceiling) that carry four, six or even eight T5 tubes of all sorts of colour combinations which will allow you to keep the most demanding of sps corals with the right placement but of course the more tubes you run the higher your electricity bill!
The other thing to consider is the unit you intend to run your flourescents from, you can buy wonderful, all singing, all dancing 8 tube units that may set you back more than £600 (which is not really what this website is about!) or, if you shop around and use your imagination you can pick up a more basic unit running 8 T5's for less than £100. I currently run one of these cheaper units running 8 tubes and am merrily keeping sps corals with no problem at all.
A lot of the above also depends on the depth of your tank, if you've made it this far into this website then I'll asume you are going for a standard tank that is no deeper than two foot. Once your tank is reaching 30" or more in depth you need to consider stronger lighting.
To summarise flourescent tubes it's suffice to say that if your keeping soft corals you can just about get away with a couple of T8 bulbs but a couple of T5 would be better. To keep anything more demanding than soft corals you should be considering either four bulb (LPS) or eight bulb (SPS) units. The price you want to pay for these units is something only you know but there are much cheaper ones on the market than the marine branded units although in fairness they don't perform quite as well. If you decide to run T8 or T5 bulbs always make sure you use reflectors as these will increase the light output for your marine tank massively.
Halide bulbs used to be the be all and end all of keeping corals. You certainly don't need them for soft corals or FOWLR tanks and they are probably excessive for many LPS. They burn more heat, use more electric and cost more than running the flourescents but there are not alot of sps corals that can't be kept under metal halides.
Metals halides also give a different look to the tank, the tank 'shimmers' which many marine fish keepers like. I have run metal halides and successfully kept just about everything under them. I switched to T5's to try and reduce my running costs (which I did) and I did miss the shimmering look for a while but the colour combinations that flourescents offer won me over in the end. The other difference you need to consider is that halides are a directional light whereas flourescents give a much more even light coverage over the whole tank. The directional light can, however, be beneficial is you are considering keeping some corals that don't like bright light (sun corals for example). I talk to many fish keepers who will never switch from metal halid because of the look to the tank but on the other hand I have also spoken to many who have changed to T5's because when you combine all the different light combinations (pinks, whites and blues) you can really design the colour to what you want.
It's worth mentioning at this point that regardless of T5 or metal halide the bulbes will need to be replaced about once per ear, this may need consideration if you are runnig a tank on a budget as it costs me £100 to replace all my T5's.
LED lighting is becoming very popular in the marine fish keeping hobby and new and better versions are coming on the market all the time. These LEDs are not normal LEDs that you sometimes see to give the tank the moonlight effect, they emit enough light to maintain SPS and also create that shimmering look of halides but without the increased heat and electricity costs that come with them. LED's also don't need to be replaced like T5 or halide bulbs and are the cheapest on the market as far as running costs go.
So they are suitable for anything you want to keep, they provide the beautiful, natural, shimmering look that halides offer and they are increadilbly cheap to run, the only issue you may have (if you are keeping marine fish on a budget) is that the initial outlay is expensive. You will need a lot of them to cover, say a four foot tank, and like halides they offer a directional light so the cover on your tank can be quite irregular.
Shed some light on the matter
If you are keeping corals under flourescent bulbs always make sure you replace the bulbs at least every twelve months.
If you decide to use halides you will not have a problem keeping almost any coral but remember that they put out a lot of heat which could be a problem in the summer if you are not running a cooler.
Lighting your Marine Tank Environment - in a nutshell
If you are keeping a FOWLR you don't need super strong lighting, a couple of T8's or T5's will be sufficient
If you are keeping a FOWLR don't use lights that are more powerful than you need as the likely excessive levels of nitrate and phosphate in your tank, along with powerful lighting will be just perfect for a massive growth in unsightly algae
If you decide you are keeping corals you need to decide which ones as different corals require different levels of light
Some soft corals can be kept on even the most modest of lighting systems
Most soft corals and a few LPS can be kept under two T5 bulbs as long as they are designed for marine fish keeping
Almost any coral can be kept under T5 lighting as long as you have enough bulbs
Almost any coral can be kept under metal halide bulbs but these are quite expensive to run and give out a lot of heat which could cause problems in the summer if you don't have a cooler
LED's are suitable for almost all corals and give the natural, shimmering look of halides, they are cheap to run and last a long time but are more expensive to buy in the first place