How much light is too much light

[buffalo123]

I read a few articles and postings which state that our reef has too much light . My guess is compared to what some corals are exposed to in their natural environment. Could this be true? Its not strange to find aquariums with 2 or 3 400watt MH. Which is alot of light. Are we running 400watt when 175watt or 150watt MH will do ?
With LEDs are we still aiming for too much light? Just how much light is right.
I do consider that most don't know the amount of light required so we may go overboard.

[Dillan]

Following!

[afishionado]

There's infinite variables in play here and you've effectively touched on none of them in any kind of necessary detail ...

Start with following:

System Statistics * i.e. dimensions of aquarium, water quality parameters, nutrient control philosophy, etc

Lighting Statistics * be very specific ... manufacturers as well

Species of Corals * Again, very specific ... Preferably down to species level, minimum Genus

[afishionado]

If you do not have specifics, pertaining to your vague questions, the following generic values will be helpful:

LPS: 50-350 PAR
SPS: 100-850 PAR

Its a widely recognized value, amongst those in the know, that photosynthetic inhibition tends to occur at ~ the 550 PAR x 12hr/day value for SPS and 350 PAR x 12hr/day for LPS.

Again, these are vague values based on the grouping of multiple species into LPS/SPS classifications, under typical high quality reef system conditions/statistics, but they are an excellent/accurate "guideline" for your information ...

Species and detailed aforementioned statistics, like those above, would be necessary for a more in depth/detailed response from myself; most likely others as well if they actually know what they're talking about

[Timfish]

Way to many variables to say. (Rules of thumb just don't work with reefs.) Here's one good example: Porites porites is found from the surface to depths of 160'. The very closely related and similar looking Porites bannerii is only found from depths of 15' to 30'. One species is very adaptable the other is not. Additionally while one species may be very adaptable it does not translate that a colony of that species would be adaptable to the entire range of environmental conditions the species is found in. These research papers:

www.mendeley.com/catalog/experience-shapes-susceptibility-reef-coral-bleaching

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034418

show coral colonies learn from or become imprinted to their environmental conditions and will demonstrate different responses to stress events.

An additional point is while it may be convenient to lump corals into broad catagories like "SPS" and "LPS" these do not have any scientific basis and have no correlation to a species husbandry requirements. If you peruse Veron's "Corals of the World" just with the Acropora genus you have species that are found in mutually exclusive environments. And some of the "SPS" are found in surprisingly murky and turbid environments like ever popular Poccillopora damicornis which is quite at home in mangrove swamps in the wild.

In my opinion an aquarists best success will be to match their environmental conditions to the conditions the corals they are selelcting are grown under (research, research, research).

[afishionado]

Way to many variables to say. (Rules of thumb just don't work with reefs.) Here's one good example: Porites porites is found from the surface to depths of 160'. The very closely related and similar looking Porites bannerii is only found from depths of 15' to 30'. One species is very adaptable the other is not. Additionally while one species may be very adaptable it does not translate that a colony of that species would be adaptable to the entire range of environmental conditions the species is found in. These research papers:

www.mendeley.com/catalog/experience-shapes-susceptibility-reef-coral-bleaching

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034418

show coral colonies learn from or become imprinted to their environmental conditions and will demonstrate different responses to stress events.

An additional point is while it may be convenient to lump corals into broad catagories like "SPS" and "LPS" these do not have any scientific basis and have no correlation to a species husbandry requirements. If you peruse Veron's "Corals of the World" just with the Acropora genus you have species that are found in mutually exclusive environments. And some of the "SPS" are found in surprisingly murky and turbid environments like ever popular Poccillopora damicornis which is quite at home in mangrove swamps in the wild.

In my opinion an aquarists best success will be to match their environmental conditions to the conditions the corals they are selelcting are grown under (research, research, research).

Thank you for transcribing/reiterating exactly what it is I was insinuating above ...

[HurricaneSystem]

I think the answer to your question/statement is yes.

I took my green brain that I bought from the LFS out of my cube and put it in my daughter's cube upstairs that has Ecoxotic LED 17.5 inch hood on it. It was about toast in my tank and it looked great at the LFS. Now, after 3 days, it looks great again. It had shriveled up to almost nothing.

I bought a sprung's chalice from another LFS and it was looking a little bad. Put it in same cube upstairs, it looks good again.

Moral of this story? Well, all of the LFS have low level LED's. Deep Blue solarfx strips and stuff like that. Just cheap, run of the mill stuff.

It is low par, but the corals seem to be doing good.

I read something the other day that was interesting too. They said a town in PA I believe, replaced all their MH street lights with LED and they had to take them down as they were too bright. Too bright in the fact that MH diminishes before it hits the ground and LED did not, it was just super bright even on the ground.

So I figure that most of us (myself included) crank these LED fixtures up a bit thinking we need more light, when in fact, we probably need less light.

Does that mean you need to keep SPS under cheap lighting? No, but I think that LED's are not there on the spectrums yet, but I also think that people are running them far too high to be effective.

Here is the other thing. We buy an LED fixture that is FAR more capable than our corals are, why? Why do we need a fixture that costs 1000-1300 dollars when we are only going to use 30-40% of the output? That makes little to no sense to me.

I bought one of the cheap LED fixtures from an LFS a few years ago, it was one of the Chinese 120w blue/white non adjustable fixtures. My corals did fantastic under that light. I still have it to this day sitting in the floor. It was just a simple on/off switch and everything did good. So it has me really wondering if we aren't over thinking these lights when it comes to LED.

MH is as close to sunlight as you can get, so of course they work. We turn up LED's to try and mimic MH. It doesn't remotely work and we end up frying our corals. I still say T5 or MH is the way to go as of yet. Just my thoughts.

[buffalo123]

Most or i should say the average reef keeper likely have a mix reef and give little attention to par; they buy a bulb ( lots of brands to pick from) if its MH 150, 175, 250, 400 watts.

Most don't have par meters or consider any more than whats written on the brand name bulb box or written online.
Other than the sps dominated reef most are mixed.
A real comparison is those who have lower watts vs higher watt MH. Some having the same corals.
Thats the the real comparisom to the average reef keepers. What they want is to see if the coral you have in an aquarium does great at 400watt and someone else having the same success with a 175 watt. (same avg aquarium depth n parameters)

[Hdhuntr01]

The answer is definitely YES. There is such a thing as lighting being to intense. Take for instance, I have Radion Pro fixtures that hang about 8" above the water. I learned by trial and error that I have to run them at 20% intensity to get the best looking corals and anemones. Even 25% intensity was too much. When you say too much light, that could mean several different things but to me it means intensity...

[PeteV_LV]

Interesting, thanks for the info.

[Holyreefer]

im actually starting to feel like my 3 250 MH are too much on my 6ft tank...
none of my LPS like the super intense light. But i know once i start to get more and more SPS it will change