[gnatp2]

So I've been on a quest to get better colors out of my corals and had moderate success, but I do have a ways to go. My current focus of improvement is the lighting of my tank. I recently went with a new sump as well as a new 150W MH Icecap pendant for it. I have placed a couple frags down in my frag grow out area and have noticed that they "lighten up" significantly (it appears to me that much of the brown zooxanthaellae go away and either the coral is bleaching or starting to show better colors).

On my main tank I am using a 400W dual PFO ballast with 2 EVC 10K bulbs hooked into spider reflectors. I also have 2 T5 actinic bulbs as well.

My question is...... How much PAR or PPFD should my sps corals be getting? In my sump it seemed to me that they were getting significantly MORE lighting than my main tank. Well, I went out and bought a light meter to confirm this suspicion. My sump light is producing 1200 PPFD (reading taken 4" under the water) while my main tank lighting is only producing 300 PPFD (also taken under 4" of water).

I've read that during the summer at noon, the sun produces around 2000 PPFD and 1500 PPFD during the winter. I've also read from Sanjay's website that most bulbs produce 90 PPFD or so.... Yes, no typos in these numbers which is why I'm confused. I've searched around but found no answers so far on what the ideal PPFD is that should be hitting corals. Obviously the answer will be different coral by coral, but I'd like to get a general idea.

Can anyone educate me?
Nate

	MH Metal Halide Lighting, typically used for high intensity light demanding corals such as SPS. Bulbs come in varieties of spectrums (7k, 10k,20k), and intensity (175W, 250W, 400W).

	SPS Small Polyped Scleractinians - Sometimes known as Small Polyped Stony corals. These are hard corals that have extremely small polyps. They are typically on the difficult side and require Metal Halide lighting or dense Power Compact or T5 arrays. These corals are prized for their rareness and ability to be easily fragged into multiple colonies.

[gnatp2]

Hello people???? This should be interesting. Lets get it going.

[Deanos]

How much light?

Water flow is more important for corals than light, Part V

Water flow is more important for corals than light, Part IV

Water flow is more important for corals than light, Part III

Water flow is more important for corals than light, Part II

Water flow is more important for corals than light, Part I

[ShaunW]

First a quick question: Is the values you give for the sun's PPFD rating at a particular depth?

Corals like nutrients! They can make most of it through photosynthesis using the zoox to generate amino acids. Bacteria living in the tissue and Ca carbonate skeleton can also undergo nitrogen fixation, generating nitrate, glutamate and glutamine. These building blocks for biosynthesis, when available, cause the coral to grow (I am mostly talking about SPS). So the answer to your question depends on many factors and how they all are available for the coral to use. These factor include and a not limited to: zoox presence at proper density, symbiotic bacterial presence for N-fixation, bacterial plankton and phytoplankton availablility, Ca and carbonate concentrations, quality of water for light penetration, and flow to remove waste and bring nutrients/food. So light while extrememly important is one factor of many. Having lower par light BUT high nutrient availability that can be directly bioassimilated can cancel each other out such that the former will compensate for the decreased photosynthesis of the zoox.

	SPS Small Polyped Scleractinians - Sometimes known as Small Polyped Stony corals. These are hard corals that have extremely small polyps. They are typically on the difficult side and require Metal Halide lighting or dense Power Compact or T5 arrays. These corals are prized for their rareness and ability to be easily fragged into multiple colonies.

[kimoyo]

Hey Nate,

Your probably not going to get a lot of answers because this is a tough question. If your concerned with colors I wouldn't worry too much about par. I would worry more about filtration and then about the wavelengths of light hitting the tank. I started looking around about this early last year, read a few days but didn't have time to really go deep into it. Plus, we all keep a lot of different species in the tank so how one coral reacts to certain light is not necessarily how another coral will react. I've seen a lot of Japanese tanks which really try to hit the corals with different colors of light. So my advice is get get some lumenarcs, go down to 250 mh so your not wasting electricty and make sure your filtration is the best it can be. Here's a post I made last year kinda on the subject.

Quote: Originally Posted by kimoyo The thing is, its not all about par when it comes to growth and coloration because par is really just measuring the intensity of light emitted. While par is important I think the spectrum is important also. This is a quote posted by mojoreef in this thread, Lets talk about ~Lighting~ (a very good read). >Pocilloporin primarily absorbs green/yellow (550-600 nm) light along with some upper UV-A . it emmits a orange/red >highly fluorescent pocilloporins primarily absorbs light from 310 to 380 nm (UV-B and UV-A) and then fluoresces this as light from 400 to 470 nm (violet/blue). >highly fluorescent pocilloporin primarily absorbs light from 380 to 470 nm (UV-A, violet and blue) and fluoresces light from 475 to 520 nm (blue and green). >third type of highly fluorescent pocilloporin primarily absorbs light from 430 to 490 nm (violet and blue) and fluoresces light from 490 to 540 nm (green/yellow). >Yellow fluorescing pocilloporin primarily absorbs light from 440 to 500 nm (blue) and fluoresces light from 520 to 620 nm (green, yellow and orange). >Red/Orange Fluorescing pocilloporin that primarily absorbs light from 500 to 540 nm (green) and fluoresces light with wavelengths that are primarily orange to red. To understand this just read that thread, but fluoresces basically means the color you see. So if you take into consideration coloring highest par doesn't mean its the best for the corals. To get some good fluorescence you want to be hitting the corals with 310-380 light. Take a look at this graph from Sanjay website (don't worry about the axis titles, all this basically means is the higher value the more light at that wavelength). Whereas the xm has the highest par (great for growth), you can see how it lacks in that fluorescence range but the ushio (lower par) doesn't. And here's a graph comparing the ushio with the blv. Very similar but the ushio has a slightly higher par. Thats why (and with its CCT) I'm somewhat surprised its more yellow. But the blv is looking like the way to go, unless the reeflux has a similar spectrum.

	MH Metal Halide Lighting, typically used for high intensity light demanding corals such as SPS. Bulbs come in varieties of spectrums (7k, 10k,20k), and intensity (175W, 250W, 400W).

[gnatp2]

Deanos, thanks for the links. I read through the first one so far and it was exactly what I was looking for. It seems that overall 200-400 Par is the zone that works best for sps corals.

Quote: Originally Posted by solbby First a quick question: Is the values you give for the sun's PPFD rating at a particular depth?

I really don't know how that reading is taken which is why I am confused. I'm only guessing that the 2000 PPFD statement that I've been reading is not at any depth whatsoever but I really don't know. Here's the quote from the first Deanos link: "Photosynthetically Active Radiation (PAR) in units of micromole photons per square meter per second (µmol·m²·sec; as a point of reference, sunlight at noon on a cloudless day in Hawai’i can be as high as 2,200 µmol·m²·sec )."

Quote: Originally Posted by solbby Having lower par light BUT high nutrient availability that can be directly bioassimilated can cancel each other out such that the former will compensate for the decreased photosynthesis of the zoox.

My tank has had <1 Nitrates for months and .03 phosphates for about 1 month now. I have finally started to see improvement in colors for the corals that are higher up in the tank in the past 2 weeks. The corals that are in shaded or lower regions of the tank have not shown improvement though. They grow well, but have brown colors. I'm thinking that this is an example of your statement about high nutrient availability but low par due to the large populations of zoox on the corals to compensate for the lack of light. (Pls clarify if I am misunderstanding you)

Also I would like to say that I agree that there are MANY other important factors (nutrient levels, spectrum, etc...) that are extremely vital as well for good coral growth and coloration, but it seems that an obvious and simple factor has got to be a reasonable amount of PAR hitting the corals. Many times the basics get overlooked.

My next goal will be to test a few other tanks that have good coloration and see if anything interesting pops up.

Nate

	SPS Small Polyped Scleractinians - Sometimes known as Small Polyped Stony corals. These are hard corals that have extremely small polyps. They are typically on the difficult side and require Metal Halide lighting or dense Power Compact or T5 arrays. These corals are prized for their rareness and ability to be easily fragged into multiple colonies.

[Slamajamajama]

good info here...

[Wes]

in my limited experience with SPS, the thing that effects my colors the most is unstable alkalinity. For example if i make an adjustment to my Ca Alk dosage and don't go extremely slow, the colors fade.

You said you are having problems with frags fading in the sump correct? I imagine you Ca Alk is being dosed directly into the sump? Not much water volume in comparison to the entire system, Alkalinity certainly could swing quite a bit in the sump before it is circulated throughout your system. Just a theory.

	SPS Small Polyped Scleractinians - Sometimes known as Small Polyped Stony corals. These are hard corals that have extremely small polyps. They are typically on the difficult side and require Metal Halide lighting or dense Power Compact or T5 arrays. These corals are prized for their rareness and ability to be easily fragged into multiple colonies.

[gnatp2]

Quote: Originally Posted by Wes in my limited experience with SPS, the thing that effects my colors the most is unstable alkalinity. For example if i make an adjustment to my Ca Alk dosage and don't go extremely slow, the colors fade. You said you are having problems with frags fading in the sump correct? I imagine you Ca Alk is being dosed directly into the sump? Not much water volume in comparison to the entire system, Alkalinity certainly could swing quite a bit in the sump before it is circulated throughout your system. Just a theory.

Wes, good advice about stability. There is an excellent thread on this board about the importance of stability in a reef tank. I am dripping my 2 part into my sump, but it is in the return chamber which should solve any issue with concentrated dosing right next to corals

And to clarify about the frag colors in my sump... It isn't that I have good colors in my main tank and bad colors in my sump, it is the case that frags in my sump have lost much of their brown color because of more intense lighting down there. I'm not happy with the colors in either area.

Nate

	SPS Small Polyped Scleractinians - Sometimes known as Small Polyped Stony corals. These are hard corals that have extremely small polyps. They are typically on the difficult side and require Metal Halide lighting or dense Power Compact or T5 arrays. These corals are prized for their rareness and ability to be easily fragged into multiple colonies.

[Tim]

Hay Nate do you want to come up to Rockland to check the par in my two tanks? LMK Tim......