Such thing as too much light?

[GaryZ]

I'm buying a decent Aqualight set up for my tank to get me started. I have a couple 400w MH lights that I'm going to incorporate eventually. I'll probably end up dismantling the Aqualight, using the fans (and adding a couple, I'm sure), the lunars, the lights and incorporate the MH's into a hood someday once I get my feet wet and learn to handle more difficult corals, clams and anenomies.

The tank is 72"X18"X30". Is this gonna be too much light? Is there such a thing?

[Steven Pro]

There is a such thing as too much light. The term is called photo-inhibition. It depends on what you want to keep.

[CSeaSee]

You may have temperature issues, too... unless you get a chiller.

[charlie]

The rule of thumb with Mh bulbs, is that they will cover a 2x2 ft. area. On a 6' tank, I don't think you are gonna have any temp problems, especially with a 30" deep tank. As far as too much lite. I have to agree with Steve, there are certain corals that like lite and others that don't. Do your research first on the lighting requirements of what you want to keep before you buy, and you and your corals will both be happy campers.

HTH

[GaryZ]

Ok, I guess I'll just have to wait and see how far I'm willing to go. I just would really like to have some clams at some point and I'm not sure if the lights I'm buying are gonna be strong enough for how deep my tank is.

[Steven Pro]

It depends on what kind of clam you ar talking about. Derasa and squamosa are very light tolerant. Case in point, I have seen both growing very well on the sand at the bottom of a 30" deep aquarium under nothing more than a combination of VHO and PC lamps. Maximas and croceas require brighter light and placement on rockwork.

[charlie]

It depends on what kind of clam you ar talking about. Derasa and squamosa are very light tolerant. Case in point, I have seen both growing very well on the sand at the bottom of a 30" deep aquarium under nothing more than a combination of VHO and PC lamps. Maximas and croceas require brighter light and placement on rockwork.

Right on Steve, good points!!

[Reefbone]

Yes (testing signature)

[Reefland]

Yes (testing signature)

Test looks good to me, and so does your tank!

[GaryZ]

It depends on what kind of clam you ar talking about. Derasa and squamosa are very light tolerant. Case in point, I have seen both growing very well on the sand at the bottom of a 30" deep aquarium under nothing more than a combination of VHO and PC lamps. Maximas and croceas require brighter light and placement on rockwork.

I don't really have a preferance yet. If I can roll with what I have without worrying about keeping SPS's happy, then I'll trade the MH's for some other stuff I need. The more I get into this, the less it seems likely that I'll get into SPS's. They don't really do much for me. They almost seem like something that people maintain just to prove they can. No offense to the SPS fans. I just always sort of lumped the SPS's in with clams, due to lighting requirements. I guess what I'm saying is, if the only thing I have to sacrifice are SPS's and most anenomies, then so be it. Thanks for the help.

[Reefland]

I think most people enjoy the SPS for a couple of reasons. 1. There is a huge array of colors available, typically not easy matched with LPS corals or soft corals. 2. The growth rate of them is much faster than that of LPS corals and therefore it becomes easier to frag and trade with friends. Just my opinion of course.

[charlie]

I think most people enjoy the SPS for a couple of reasons. 1. There is a huge array of colors available, typically not easy matched with LPS corals or soft corals. 2. The growth rate of them is much faster than that of LPS corals and therefore it becomes easier to frag and trade with friends. Just my opinion of course.

I also think the challenge of trying to keep your water parameters to the point where you can keep the sps. Don't get me wrong, I love my softies too, I just really enjoy the challenge that sps give me.

[Ninong]

This question has been asked at least two or three times before. Here is another thread with almost exactly the same title: Too much light? Such thing?

Here is what I posted in that thread:

how can you have too much light?

Any light exceeding the zooxanthella's saturation point is too much light. If it greatly exceeds the saturation point it can result in photoinhibition. Dynamic photoinhibition causes reversible photochemical reactions that divert excess light energy away from Photosystem II through thermal dissipation but chronic photoinhibition causes irreversible damage to Photosystem II where synthesis of new photosynthetic proteins must occur before normal photochemistry may resume (Brown, 1999).

Saturation points for most corals are reached at 20-30% PARS (photosynthetically active radiation at the surface), some as low as 10% PARS and a few as high as 90% PARS (Sorokin, 1995). Photosynthesis can proceed as long as a coral's compensation point is exceeded. It isn't necessary to actually reach it's saturation point and anything above its saturation point provides no additional photosynthesis whatsoever. Greatly exceeding its saturation point can result in photosynthesis shutting down -- photoinhibition. Corals found in shallow water habitats have adapted to extreme light conditions but even they can be damaged by excessive exposure that can happen when the sea level drops drastically such as during an El Nino year.

The problem for aquarists is that not all of the corals we keep are found in shallow waters. Some commonly inhabit waters 10-20 meters deep. These corals would be damaged at light intensities lower than those that would damage corals found in shallow waters. If one were to locate a 2000w metal halide lamp -- or even a 1000w lamp -- too close to the surface of the aquarium there are many corals that would be unable to adapt to such intense light. A 2000w metal halide lamp produces 170,000 lumens. That greatly exceeds maximum noon sunlight in the tropics. And don't forget that the light intensity at 5 meters depth is only one-fourth that at the surface.

The original question was not whether the average hobbyist can have too much light using the usual 250w and 400w metal halide lamps, the question was whether there is such a thing as too much light. Yes, there is.

[GaryZ]

That thread don't count. It's over a year old.

[chevell]

Very easily done,in fact I can't even run more than 4 bulbs on my VHO only tank with three of those lights being actinics.I have countless ORA sps's and many other types of sps and they don't like too much light at all.I have 8 bulbs total but I have to stagger them so they are not running all at the same time ever.This is a true fact that VHO are much brighter than any halide system but the problem with that being sps's don't like very much light anyway.

[Ninong]

This is a true fact that VHO are much brighter than any halide system...

We are all entitled to our own opinions but not our own facts. The claim that VHO are much brighter than any halide system is obviously false and can be proven false by simple measurement with any available luxmeter or an inexpensive Apogee PAR meter.

I will bet you any amount of money you wish to lose that you cannot measure higher intensity under VHO lighting than you can under a single 1000w 10,000K metal halide lamp.

[charlie]

Rob,
Can we see some pictures of your reef. I, in fact would be interested to see how I can cut my electrical costs.
Does your reef catch any natural sunlite?
I also noticed that you have 40 years in the hobby, that's pretty impressive, but I don't see any pics anywhere???????

[Reefland]

...the problem with that being sps's don't like very much light anyway.

Tell that to the colonies of Acropora spp., Monipora spp, etc. that stretch for miles in swallow reefs that are also exposed to the air and sunlight at low tide.

[Steven Pro]

(Brown, 1999) & (Sorokin, 1995)

Do you have the full citation for these papers? I am always interested in learning more from the scientific literature. I would love to pick up copies to read for myself.

[Ninong]

Do you have the full citation for these papers? I am always interested in learning more from the scientific literature. I would love to pick up copies to read for myself.

I have (or I should say I had) a copy of Sorokin's book Coral Reef Ecology (1995) but I recently sold it to Mark Felton (MiddletonMark). It is an excellent book filled with data from scientific studies performed by Sorokin and others on the GBR over the years. He works in Australia. The book was written in his native Russian, then translated from Russian to German and finally from German to English. It is filled with typos and some of the grammar is tedious in the extreme but it is still an excellent source.

All of the sources cited are available using Google's Advanced Scholar search function. It's just that many of them are just abstracts and you have to subscribe at an enormous annual fee to gain access to the full paper. Some papers are available in full but many are not.

Google: http://www.google.com/intl/en/options/ Click on Scholar.