How important is light for SPS corals?

[weaglereefer]

Dakota9;395884 wrote: Odd that corals would be saturated at 200/par as I remember one meeting (during a slide show presentation I believe), a lady was telling us that much (or twice that much) par was achevied by 7am on the natural reef.

Don't think it's that odd. Corals have been around for millions of years; it would make sense that they are very efficient at converting light to energy, and unless there was some specific advantage to gain, it would not fit that corals would evolve to NEED more light. If anything they would evolve to need less light (non-photosynthetic gorgonians and sun corals anyone?). Now they may be able to withstand higher par, and they may be able to use extra light, but to say it's "needed" is where the muddy area lies.

As for feeding causing more growth, that doesn't surprise me at all. I think most reef hobbyists are aware that feeding corals can make them grow faster, especially with LPS corals. Were they feeding brine shrimp to SPS too?

 

[jason sartain]

I think the only thing MORE light grows is MORE algae!!!But,I've been wrong before.

 

[lilrobb]

I might be able to scan it...
Let me try

 

[sailfish]

Here is one of Dana's articles on light intensity. If you look some of the corals are not sps at all and other sps are montiporas which we all know do not require that much light. His articles on light intensity and coral colors are made up of at least 9 different articles. So reading one and making a decision on it alone would not be very beneficial.

http://www.advancedaquarist.com/2007/3/aafeature1/view">http://www.advancedaquarist.com/2007/3/aafeature1/view</a>

Look at the graph Fig #13 and see coral color for this species increases as the amount of light increases.
[IMG]http://www.advancedaquarist.com/2007/10/aafeature2/view">http://www.advancedaquarist.com/2007/10/aafeature2/view</a>

If you look at the bottom of the articles there are links to all the other articles. I believe you can find proof to make an argument for both sides. There can be a big difference between what it takes to keep a coral alive and growing and one that looks great.

Joe

 

[lilrobb]

Agreed Joe,

their studies were solely on growth - they didn't even mention coloration at all in this...

 

[snowmansnow]

well in nature.. i guess growth is the only thing that matters... its we hobby goers that want things to look pretty

B

 

[coolsurf]

Not trying to hijack but here's an interesting aticle on light and water flow...

 

[acroholic]

I had good growth and color on ORA SPS frags that were at the bottom of my 210, and I had about 200 PAR at that level.

Another thing that can help make up for a lower PAR is a longer Photoperiod. I discussed this with MOJO at length a few months ago, and while a longer photoperiod is not direct replacement for higher par, it can help make up some of the deficit.
Dave

 

[acroholic]

ares;395989 wrote: which presents the experiment I still need to try... if higher par produces photoinhibition in only 2 or 3 hours, and Ive read other places it only takes about 6 hours for a coral to "reset" in a period of darkness. you could hypotheticly get 2-3 "days" of growth in 24 hours by doing 2 hours on, 6 hours off. maybe... might need to get the fish a shrink though.

Man, I wonder what that amount of "on and off" would do to the lifespan of the halide bulb?

 

[skriz]

Acroholic;395994 wrote: Man, I wonder what that amount of "on and off" would do to the lifespan of the halide bulb?

You could get around this by using multiple fixures; each running at different times, so one bulb isn't turned back on during the day? OR, those 2 filament bulbs Jake Adams was talking about..

 

[theplatypus]

How often and how much Artemia was being fed?

 

[lilrobb]

Quick answer:

Best results were obtained at 1000specimen per milliliter, but that also led to elevated nitrate levels due to the high concentration - 300specimen per milliliter was agreed to be the best mix.
This was dosed daily with only 2hour old artemia...

 

[theplatypus]

LilRobb;396052 wrote: Quick answer:

Best results were obtained at 1000specimen per milliliter, but that also led to elevated nitrate levels due to the high concentration - 300specimen per milliliter was agreed to be the best mix.
This was dosed daily with only 2hour old artemia...

Is that per milliliter of tank volume?

 

[lilrobb]

theplatypus;396055 wrote: Is that per milliliter of tank volume?

Oops,

that was the concentration in the food container.

They dosed 10liters daily (at this concentration) into a 50.000Liter tank system - so that should be a concentration in the tank of 200 artemia per LITER!

 

[theplatypus]

LilRobb;396058 wrote: Oops,

that was the concentration in the food container.

They dosed 10liters daily (at this concentration) into a 50.000Liter tank system - so that should be a concentration in the tank of 200 artemia per LITER!

edit

misread your post

That's still a whole pile of brine shrimp hatching.

 

[weaglereefer]

300/milliliter = 300,000 / liter

10 liters = 3,000,000 artemia

3,000,000/50,000 liter tank volume = 60 artemia per liter

3.78 liters in a gallon * 60 artemia = 227 artemia per gallon


You can figure out what you need from there. How many brine shrimp come in a pack of sea monkeys? I couldn't see doing this on a display tank, but a frag tank, now that would work if you had the water systems seperate or a huge skimmer. A 20 gallon frag tank would need roughly 4500 artemia per daily feeding...

What were they using that they had it concentrated in bottles? Seems like a lot of the benefit of brine is when they hatch new. Is this stuff kept refrigerated so they are kept in suspension?

 

[sailfish]

Inspired by this thread about a week or two ago I cut a frag of Green Austera and put it in my Refugium to see if it would live in very low light. It is still alive so I thought I word get a little more organized about it.

The Refugium is lit for about 20 hrs a day and has a par were the frag is located of 36.
The coral is 7/8" tall measured from the frag plug to the tip.

The coral is still alive but has not encrusted at all. I will leave it in there for another 4 weeks and see how much it grows if any. If it dies I will let everyone know.

Pic week 1 Oct/14/ 09

alt="" />

Joe

 

[hackman72]

Cool. I'm kind of anxious to see this.

 

[weaglereefer]

I'd be curious if different colored corals could handle lower amounts of light. I'm curious to see the color of this piece if it survives in a few weeks.

 

[sailfish]

I bet it lives but will be brown and will not grow much if any.

Joe