Lighting rules of thumb?

[bureau13]

I've read a lot of lighting rules of thumb, but they don't really make sense to me, and seem inconsistent. For instance, I've read that you need at least 5W/gal (I've also read more like 7W/gal..I know, it depends on what you're keeping) but I've also read that T5s are more efficient than PCs, M-H lighting penetrates better, etc. Is there any consensus on which of these (if any) are accurate?

jds

[egdevilboy]

Okay, id go with 5+w/gallon for most corals.

T5s burn alot cooler than PCs and are much smaller, which inturn makes them better. But remember they are much more costly (i run PCs for that fact)

For SPSs and Clams you would need MH lighting.
Metal Halides are the closest lighting to the sun. This being said, MH do run hot but will provide alot of light from a single bulb.

[bureau13]

Its so weird...I just read an article by Bob Fenner where he seems to suggest that M-H lights are not needed for most reef systems. I respect this guy's experience tremendously, but this just flies in the face of everything I've ever heard.

I also read an article by Anthony Calfo where he says you shouldn't have M-H bulbs where the naked eye can see them due to the UV energy, and he recommended a canopy...but one of the fixtures I was considering (by Aquamedic, but I'm sure this applies to many others) says that its not recommended to be enclosed in a canopy. I know you can't put these down close to the surface...what are you supposed to do?

jds

[Avi]

There are tons of ways to light a reef. I used to use power compacts....about 5-watts per gallon on my 120-gallon reef. But I found that I was only able to get coral to do really well up towards the top of the rockwork. That was soft coral and LPS that I had. The bottom three qaurters of the rockwork was barren of coral in my 24-inch deep tank. There is a very credible member here in RC that has more than the 5-watts per gallon in a tank as deep as mine is, and says that he can grow coral anywhere in his tank and does. So it might be that you have to place tons of PC lighting on a deeper tank for that kind of result.

I've read in many places that t5 lighting is fine for reefkeeping and it's my understanding that it's used more widely in Europe...Look around this forum for other threads on this subject.

I changed over to metal halides, and I can tell you from my experience, that while power compacts were okay, I guess, for me for a while, the metal halides allow me to grow coral anywhere in my tank, including on the bottom and in fairly shaded areas. I have to say, in my experience, it's just an overall better option. Don't get me wrong, in a shallower tank....say, up to 18-inches deep, you can use power compact with more overall success than in a deeper tank. But, if you are committed to keeping a reef for the long haul, start with the metal halides so you won't be tempted to change over to them later on, especially if you may ever intend to keep SPS.

[Wryknow]

The DE bulbs should have UV shields on the lenses so I wouldn't be too worried about UV radiation causing problems for your eyes. Use common sense on this one - you don't want to stare directly at a bulb obviously. I would not try to put an MH bulb into a canopy [personally although plenty of people do it successfully - it's largely a matter of which problem you would rather deal with and what your aesthetic sense dictates.
Unfortunately the watts per gallon rule of thumb can be very misleading. The bottom line is that watts is a measure of power consumption and your corals don't care didley-squat about what your electric bill is. They care about how much light they are getting!
A lot of people use PAR value to make a more accurate assesment of light reaching a coral. PAR is a measurement of how mush light is striking a sensore at a particular location. This is not a "gold-standard" though because some aquarists feel that but even the PAR value can be mis-leading because corals may (or may not) be adapted to using all parts of the lighting spectrum. (Light in the ocean tends to be blue because the water filters out the yellow and reds spectrums more efficiently.) Yellow (lower K lights) give off the most PAR but not all corals may use the lower-K light as efficiently as they do a higher K light.
Bottom-line is that the answer to almost every answer in reef keeping should start with "it depends." For a shallow tank with less-demanding corals PCs work just fine. For a deeper tank you will want to consider T5s or metal halide. The aqua-medic MH/T5 combos seem like the best of both worlds to me and are fairly inexpensive by reefer standards and that is what I currently recommend to people that ask my advice. You get what you pay for though!

[bureau13]

I did look at the Aquamedic lights (I found the series with the 10K and lesser-powered 20K instead of actinics to be intriguing) but they only go up to 250W lamps. For a 36" tall tank, and wanting the ability to be somewhat flexible about coral placement, I think I'm going to need the 400W bulbs.

jds

[Skepperz]

Can anybody tell me if these MH lamps are any good?

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=7740984879&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1

What is the difference between an electronic ballast and these? ATCO OmniPak?

[shag26272]

bureau13 just a little info, I just heard that the aquamedic facility burned to the ground

[bureau13]

Ouch! I hope they had good insurance...it would be a blow to the industry to lose those guys.

jds

[kelly_and_brian]

This is such a weird subject. I had similar issues, and have still not resolved them. It sure seems like the rule of thumb should be lumens/inch of tank depth (or meter if you prefer), rather than watts per gallon.

At the LFS last weekend there was a 150 tall and next to it was a long/shallow 220, and I would bet you would need more light for the 150 than the 220 to have the same growth experience.