Ideal PAR ranges for SPS dominant?

[zack801]

i recently bought a Neptune PMK because I was curious how much PAR my tank was actually getting after just guessing all these years. I’ve got a 48” 6bulb TEK T5 with ATI bulbs and reefbrites on each side. I’ve got thaibganging 9” awl on a 12” deep growout tank. At this height in the middle of the fixture I’m hitting around 400par. My question is I know a lot of people keep certain acros at much higher par. What range is ideal to keep the majority of acros? Meaning absolute lowest you would consider and absolute highest.

 

[Crabs McJones]

i recently bought a Neptune PMK because I was curious how much PAR my tank was actually getting after just guessing all these years. I’ve got a 48” 6bulb TEK T5 with ATI bulbs and reefbrites on each side. I’ve got thaibganging 9” awl on a 12” deep growout tank. At this height in the middle of the fixture I’m hitting around 400par. My question is I know a lot of people keep certain acros at much higher par. What range is ideal to keep the majority of acros? Meaning absolute lowest you would consider and absolute highest.

I believe BRS did a series of tests on that very question, and the end result was 250-350 par. With that being said I have seen people keep SPS in as low as 150 par a other tanks with upwards of 500 par. In my opinion its all a matter of adaptation. Corals can adjust to a wide variety of lighting. If you're hitting 400 par and the corals have been under that for a while, I wouldn't change anything

 

[zack801]

I always wonder though what I can tinker with to get the best growth and colors. I’m always tempted to up the par or reposition frags to see how they react to changes with flow and lighting

 

[jda]

I think that nearly all high-light acropora will do pretty well with 400 PAR. Sure, they can handle more and it might even have a bit better growth and maybe some slightly brighter colors (debatable), but this could be totally minuscule and probably not worth chasing.

If you want the "best possible" then a 10 bulb T5 or MH would probably grow faster than what you have. This is no "tinker," though, but kinda a paradigm shift.

For the lowest PAR, I keep deep waters in 175-200 and they do great. For highest, I have some efflos and stuff under 700+ PAR and they do great too, but I also think that they would be find under the 400 that you have. When I get in wild colonies from time to time, I try and get as near to 1000 PAR with 6500k bulbs as possible when they first land - this is about half of what they got in the wild.

Most SPS can take a ton of light, but it is very clear that most do not need a ton.

I do think that light "quality" matters here. Some of this depends on where you come out on the Emerson Effect - I believe in it, and the light sources that I use have IR and if the Emerson Effect is correct, then coral can process and use more light than without IR. Some people are not sold on it... some are. To each their own. I do believe that lights with IR can be blasted higher without damaging corals.

 

[marlinmon]

I was blasting a birdsnest with over 1,000 par until recently. It was doing great. I had one short cake acro at 800 and was doing great too. Most my acro is at 200-300. One has great growth at 150... so I guess it depends

 

[hart24601]

It will also depend a great deal on flow. I frequently see PAR talked about, but remember you need to increase flow if you increase PAR, if all else remains the same. Heck I kept frogspawn in 600-800 PAR for a year with good growth but it was in a whole lot of flow. Lower flow and light produced greater extension in them, so it wasn't ideal, but it's what I had.