Lighting - What does it mean?

[jpeterson]

Please note:This article and pictures were taken from my website and was written by Stephanie Abbott, if you wish to use this article please message me for prior permission.

Many websites and livestock sellers use very generic terms when describing the lighting conditions corals need in order to survive and thrive. The reason for this is that it's very difficult to sum up appropriate lighting requirements for corals, mostly because there are various types of bulbs and fixtures available as well as the height of a tank making a large difference.

Many times bulb "reflectors" will be mentioned when determining what category lighting you fall into. It is always recommended to get a lighting fixture that comes with INDIVIDUAL reflectors on each bulb, rather than one large reflector around all of the bulbs. Individual reflectors can increase light output by up to 300%! Don't have them on your fixture? A little DIY can go a long way... Many fixtures can be modified to have reflectors added to them for an instant upgrade to your lighting.

There is such a thing as too much light. Two 250watt halides on a 12" tank will not cause your acropora to grow faster... it will causes it to bleach and die.

Linnaeus uses the following terms when describing the lighting requirement for corals: low, moderate, high, or none (in the case of non-photosynthetic animals). Here are some guidelines to help you determine what category your current lighting falls under, separated by tank sizes.
*** PLEASE NOTE: This is only a rough outline. Nothing in this hobby is straight forward or predictable. For example: Some fixtures rated as "moderate" lighting may be able to support "high" lighting corals if placed very high in the tank and/or supplemented with additional food.
*** ALSO: We are assuming you are using the appropriate length of bulb for your tank... (i.e. 48" fixture on a 48" tank).

Very Short Tanks - Height: 10" (25cm) or less

Nano tanks have one large advantage to them, and that is lighting. Being so short, the most simple of lights can support corals that generally require much higher levels in taller tanks.
One power compact or T5 bulb should be enough to do just about any coral in a tank this tall. Because of the fixture having only one bulb, it should have its own reflector. This would qualify you as having high lighting.

For those of you with T8s, one bulb would be plenty for you to qualify as having moderate lighting.

LEDs have become more popular with smaller tanks. Something like Azoo's neo LED light or similar can very easily support soft corals (placing them into the low lighting category), however, I have not seen very good results with LPS corals even in the shortest of tanks.

Short Tanks - Height: 11"-15" (28-38cm)

A two power compact or T5 bulb fixture with individual reflectors should be plenty to qualify you for high lighting. For fixtures without reflectors, it is recommended to have at least 4 bulbs, with 6 bulbs being better to fall into the high lighting category. It may be possible to have only one bulb and to support high light corals, if they are placed very high in the tank.

A fixture containing one power compact or one T5 bulb with individual reflectors will put you into the moderate lighting level. Without individual reflectors, a unit with 2-4 bulbs will put you into this category.For the low lighting level, a single T8 bulb (standard in many hoods) will put you here.

Please note that metal halides are likely to be way over kill on the smaller height tanks, even for the "high lighting" corals. Too much light will cause fading and bleaching.

Medium Tanks - Height: 16"-19" (40-48cm)

The following would be considered high lighting for these tanks: standard metal halide unit, 4 or more bulbs of either power compact or T5s, each with individual reflectors. For those without individual reflectors, 6 bulbs of either power compact or T5 would be best to get into this category. With two bulbs with individual reflectors, high light corals may do well if placed up high in the tank.

To qualify for the medium lighting category, a fixture containing 2 power compact or T5 bulbs with individual reflectors would be needed. Without reflectors, a 4 or 6 bulb fixture would be needed.

For low lighting, a single power compact or T5 bulb would be adequate. 1-2 T8 bulbs may be able to support very low light corals (ie. Mushrooms and Zoas).

Tall Tanks - Height: 20"-24" (50-60cm)

Metal halide lighting (more commonly either 150 or 250 watt) would be considered high lighting for these sized tanks. Many tanks this size have a middle brace on top of the tank, therefore more than one metal halide is recommended (on either side of the brace), in order to prevent dim spots on the edges of the tank. 4 or more T5 bulbs with individual reflectors will be suitable for high light corals, as long as they are in the upper levels of the tank, otherwise 6 or more bulbs is recommended.

Medium lighting, 2-4 bulbs of T5 or power compacts with individual reflectors. 6 or more bulbs if no individual reflectors are present.

For low lighting, 2 Bulbs of T5 or power compacts will allow good growth for corals. As low as 2 T8 bulbs is possible for very low lighting corals (ie. Mushrooms and Zoas).

Very Tall Tanks - Height: 25" (63cm) or more

***Please note***: Because this is pretty much 25" to INFINITE height, suggestions here are not fixed and vary greatly depending on exactly how drastically tall the tank is.

With a tank so tall, nearly all people would opt to go with at least two metal halide fixtures (potentially more depending on the length of the tank). Multiple 250 watt fixtures should be plenty of lighting to do just about any corals. Additional bulbs of T5 would be great supplements especially for color.

Happy Reefing!

[CollegeReefer]

Not a bad little write up. When was it written? I have no clue who Stephanie Abbott is. Should I know who this is? What is your website? I still think this article over simplifies lighting and might be a little out of date with its comments about LED’s. I have to run but I will write up a response to the article later. Thanks for posting and welcome to the forums. I saw a pic of your planted tank and I have to say you did a wonderful job on it.

[funlad3]

Yeah, everyone, please review this, as it fits in directly with my "Let Me Let There be Light" thread. To me though, the statistics sound pretty close! Very simple (Too simple? I'll let the pros decide...)

-Thanks for posting and welcome to FishForums!

[jpeterson]

My website is a information website and i am not sure im allowed to post it as it has an online store on it. Stephanie Abbott is someone who works for me and runs the salty side of my website

[TheOldSalt]

If you look around a bit, you'll find that we have a place just for people to post links to their own sites. Your site's link would fit there nicely.

[jpeterson]

Originally Posted by TheOldSalt If you look around a bit, you'll find that we have a place just for people to post links to their own sites. Your site's link would fit there nicely.

Ahhh, Ta much! Will post it when its closer to being finished!

Also, the LED comment. LED are not popular and are very very expensive so the info isn't out of date. It just that there isn't much info on them because they are not common.

[CollegeReefer]

Originally Posted by jpeterson Also, the LED comment. LED are not popular and are very very expensive so the info isn't out of date. It just that there isn't much info on them because they are not common.

Really? Maybe by you but LED is takening off here in the states. Several members of the reef club i belong to already made the switch with more switching soon. Right now the cheepest way to go is DIY route. For around 300 you can but together a nice DIY fixture with 3 watt cree LED. Check out RapidLED for DIY parts.

[CollegeReefer]

This was a nice little write up and will be great for your customers. Here are a few of my thoughts.

It is refreshing to see you mention the reflectors for this is a very important part but ballast, bulb brand, bulb color temperature also play huge roles in lighting.

Some will argue that you can never have too much light especially in the case of coral health. The sun outputs a lot more light then most hobbyist provide in the home aquarium. I was looking for an article that I once read about this but it is currently eluding me. Bleaching really only happens when you don’t properly acclimate your corals to your lights. We had a club member just upgrade his lighting to an ATI sunpower t5 fixture and didn’t use screen to acclimate his corals which then started to bleach. After he noticed the bleaching he added window screen to lower the light a bit and gradually removed the screen over the duration of a week or two keeping his corals happy. Does he have too much light for his aquarium? Nope just the corals didn’t know what to do with the extra light.

Tank depth does play an important role in selecting a fixture but doesn’t necessarily determine how many bulbs are needed. For instance I have a standard 120 gallon tank which is 48x24x24. My depth is 24 inches but I would use either an 8-10 bulb t5 fixture which would give me enough light to keep sps throughout the tank. A 90 or 75 gallon tank would be fine with a 6 bulb fixture. I should also note that with a 48” tank I would be using 54 watt bulbs. Your tank dimensions play a bigger role in picking what size bulbs are needed and how many are needed. Selecting the bulbs is the easy part. The hard part is selecting what bulbs you want to use. Different bulb temperature promote color while other promote growth. Selecting a combination that can offer the look you want while offering good growth and color can be a tricky and time consuming but with a little research you can see what most are using. In a different thread I referenced Grimreefer site which is very helpful. He is the go to guy on a different forum I visit frequently.

MH is still the go to lights for SPS and LPS although T5 picked up some ground especially with mixed tanks. LED will be replacing the need for MH in the next few years. MH can offer decent light with a standard reflector but with a reflector like a lumenbright your PAR readings will increase a lot. 250 watt bulbs are often used in tanks less than 24” but I have seen many builds that utilize 400 watt bulbs in your standard 120 and 180’s. Any corals can be kept in high light as long as they are acclimated to your light. Many coral farmers use to use 250 or 400 watt bulbs in there grow out tanks but many are starting to switch to LED. As with the t5 the number of MH needed depends on your tank dimensions not depth. A 120 like I have will need two reflectors and bulbs where a standard 180 would require 3. Most people with 90 cube tanks use 1 lumenbright reflector and 1 250 or 400 watt bulb.

LED has come a long ways since I started in this hobby. I believe I saw my first LED fixture in person while I was attending the Dr. Foster and Smith frag swap. At that time you were getting the best PAR readings and the fixtures were very expensive. Today though LED are everywhere and are becoming more practical for your average reefer. Fixtures can still be expensive especially when comparing to the cost of MH or t5 fixtures but most forgot about the saving on these fixtures. LED bulbs are expected to last 50,000 hours which if you run your bulbs 10 hours a day will last you over 10 years. With MH and t5 you have to change bulbs at least once a year. Many change them even sooner especially if the bulbs are being overdriven. My reeflux MH bulbs cost 80 bucks each and I need two of them so over 10 years that is 1600 dollars. On top of bulb savings you also have energy savings which is where LED really shine. So although the fixtures are more expensive you can recoup your investment over a few years. Because it doesn’t seem like you are aware of LED fixtures here are a few that are very popular here in the states. Aqua Illumination, Bluemoon, coralsky, ecoxotic LED. These lights are still a little expensive but offer some of the best PAR readings. There are also cheaper options that are still showing respectable PAR readings and are fraction of the cost of Aqua Illumination LED. Several members in our club have switched over to LED by buying the Evolution LED fixtures which are only 299.00 for a 119 watt fixture. The downside to the evolution LED fixtures is that they are using 1 watt bulbs where the Aqua Illumination is using 3 watt bulbs. Here are some PAR readings from the Evolution taken by a friend of mine and the Aqua Illumination taken from a different forum. Evolution 119 watt fixture: 1 light 5" above water line shows 926 PAR at surface, 565 PAR 5" underwater, 263 PAR 19" underwater, 115 PAR 23" underwater at the sandbed. AquaIllumination: 6” 1650, 12” 1370(water surface), 16” 915 (4” water depth), 19” 690 (7” water), 24” 560 (12” water depth) 48” 275 (24 inches). As you can see they offer some great PAR readings.

Finally I want to point out that some of your bulb suggestion wouldn’t be enough for even softies. In my 75 gallon tank I was running two 250 watt bulbs with a standard reflector and magnetic ballast gorwing mostly softies. The tank was dominated by polyps, leathers, and mushrooms. I saw more growth then I saw in my 24 gallon tank which was using power compacts. I doubt I would have been able to keep the zoa from melting if I only had two t5 bulbs in my 75 gallon. Also I should note that corals can often survive is less light but you will not be able to sustain the color of that coral. With that said I have to run because it is snowing and I am going to go for a walk with my wife.

[jpeterson]

Thanks for the brilliant reply! Ill be discussing this with the team at Linnaeus to see of any additional changes. We will not be doing any changes which regard LEDs until they are a big competitor with T5's. The article is intended to give rough guidelines to customers on which lighting to select. We tried to make the article leave as much to the customers imagination without guiding them to buy something that would be unsuitable for their coral and tank. I know from personal experience i went through about 10 bulbs in a month until i found the right look for me. We though if we provided a article that sums up the basics of marine lighting then we could get the customer being able to get the right lighting for them without having to go through 10 bulbs which means we save them some money. This article connects with all of our coral pages. We suggest the lighting of which you would need in the coral articles. We suggest either high, medium, or low lighting. There is then a link beside the lighting which takes us to this article. First the customer looks for the height of their tank then reads which ever lighting (high, medium or low) section for that tank height which gives them basic info and guidance to which bulb will assure their coral to live happily in.

Hope that helps give a better understanding of what the article is about and what it's intended to do.

[jpeterson]

The reply from the lady who wrote the article was...


As with everything in this hobby you're going to find people who have varying opinions and while some of what he said I agree with, a lot I do not agree with. I have been reefing quite a few years and I use personal experience to guide me for almost everything I suggest to others. I definitely disagree with having too much light. Yes the sun gives off more light, but corals are found at varying depths in the ocean to reflect this. We have a very short tank at the moment with 2x 250w MH on it and the corals are bleaching the power. It is not because they weren't acclimated and they do not bleach right away. I am positive that is what the problem with that tank is and when the fixture is finally switched out and everything is doing well again, I will be happy

He/she comments he/she would use a 6 bulbs on a 75, I currently have a 75 with only 4 T5 bulbs and the corals are doing fantastic with no color loss.... I will also comment that several people who have softies with VERY low lighting which are doing amazing. They only have 2 T8 bulbs on his 60g tank and is able to keep a variety of softies.

LEDs are yet to be my forte, I have only researched into them a few times when I, myself, was debating on using them and decided not to.

Opinions differ... and I respect his/hers, but I do not agree with some of it.

Also wanted to mention that he/she is right in saying that there are many other factors that go into lighting, but what I wrote was going to be very basic. This article was meant for beginners and If i added every portion of lighting, I fear I would be going over most people's heads. I am satisfied with what I wrote for Linnaeus.

[CollegeReefer]

I guess I should clarify my statement that you can’t have too much light. It is well known that most soft corals and LPS don’t need as much light as SPS. Soft corals and LPS corals can suffer from photoinhibition. A SPS dominate tank however needs a lot of light especially ones collected from shallower water. When it comes to lighting for corals we are trying to reach the saturation point which in many cases can’t be obtained in the home aquaria. Anthony Calfo writes in Book of Coral Propagation, “The amount of light required to replicate levels of illumination that some shallow water species of coral receive on a reef would practically boil the water of most aquarium displays (Calfo 96).

If corals need so much light that we can’t provide in the home aquaria then how do they survive? Calfo mentions that the reason many corals can thrive in the home aquarium is because they are being illuminated to the compensation point for photosynthesis. This is to say enough light is reaching the zooxanthelae which is creating enough glucose for energy to be produced during respiration and in turn creates a source of carbon for the host to maintain vital functions (Calfo 96). This is why in the home aquarium we need to increase feeding of the corals because the zooxanthalae doesn’t have enough light to create the amount of “food” the coral needs. I should note though that feeding can only do so much. Calfo reminds the reader that because some corals seem to be surviving doesn’t mean they are thriving. “A one percent net deficit below the compensation point will not be apparent to an aqurist after a matter of days or even months but a coral operating at theat level will eventually die.” (Calfo 96)

So what does this all mean? When selecting light you need to know exactly what you want to keep in your aquarium which most new hobbyist don’t know. If it is going to be SPS dominated you need a whole lot more light then if you are going to have a softy tank. Many hobbyist set up mixed tanks which increase the difficulty of successfully keeping your corals happy. A few of my friends would complain that there sps wouldn’t color up even when placed near the top of the aquarium. This is because there isn’t enough light for the SPS, but if they up the light to make the SPS happy the soft corals and won’t be happy. This is because these different species might have 70 feet of water separating them not to mention different water movement.

So in conclusion it is possible to have too much light (photoinhibition) but in the case of aquarist who are looking to have a SPS dominated tank this isn’t really true although there does become a point where trying to add enough light isn’t cost effective because of heat created by the lamp. It all comes down to what species of coral you are going to have. Even in your SPS species the lighting requirements are different. For instance Acropora millepora doesn’t need as much light as Acropora microclados but they are both considered to need high light. This is why we (fishfourms) are an advocate of education because there is so much to learn when coming into this hobby. We try to help as much as we can but we push the new aquarists to read some books to not only learn but to get a better idea of what they want. I once read that 1 in 4 new hobbyist only last a year because they didn’t take the time to educate themselves about the hobby. Most who leave the hobby (until recently) leave because of a tank disaster.

[CollegeReefer]

I should add that I do understand that opinions differ and that for your website your little intro to lighting is a great idea but I want to encourage any new hobbyist on fishfourms to do further reading on the subject. One thing I would like to see added to your little guide is about bulbs and bulb life. Too many new hobbyist neglect there bulbs which I did early on in the hobby

[CollegeReefer]

May I also add that I didn't know t-8 were even used in the reef industry anymore. I didn't think they provided enough light even overdriven.

[TheOldSalt]

heh. I used to get pretty good results from T-8's, but nowadays I wouldn't even consider using them if I could avoid it. I still can't afford LED, so that makes me a T-5 guy. In fact, I just ordered a new T-5 doublestrip for a 20-long destined to be a new reeftank in about two months. It's a shallow tank, so that should work well enough, eh? I'm thinking that this tank will be Zoanthid City, with maybe some cool Rics or Acans.

[funlad3]

"I once read that 1 in 4 new hobbyist only last a year because they didn’t take the time to educate themselves about the hobby."

I had to read this sentence four times for it to make sense!

Also, I'd like to again thank those who ad good input to these discussions; although books are informative, everything is a lot easier to learn and understand when it comes from multiple people. (The exception, look up a few lines)