Low PAR increase photosynthesis?

[dave57]

I've noticed now days that the trend is to have high par values with our led fixtures for better coloration/growth but in reality does it really cause faster growth?

Dana riddle at macna 2016 recently discussed the correlation between light, flow and alkalinity and how they can be tweaked in order to obtain higher rates of photosynthesis.

Has anyone here experienced faster growth rates at lower par levels 100-250 with high light requiring species of sps?

 

[Daniel@R2R]

Interesting question. Following.

 

[saltyfilmfolks]

Diesel does. But he's on T5, so the question of PUR comes to the table. Generally the 250 on some species.
edit, and no I would disagree about high par today w led. A MH will kick out the par pretty hard. In fact I would say I observe the exact opposite.

 

[mcarroll]

So few people actually measure their lights and even fewer weigh their corals to determine growth.....plus there are so many more factors than light at play, especially at the extremes of high and low light.

I can tell you that I run two tanks of mostly the same stony corals. One gets about 40,000-50,000 lux from a 27" Maxspect Razor. The other tank gets about 10,000 lux from a DIY fixture. All measurements at the water surface.

Corals grow pretty well in both tanks....if they grow faster or slower in one of the tanks, it's almost imperceptible. My gut says the brighter tank grows faster though.

 

[saltyfilmfolks]

My gut says the brighter tank grows faster though.

If you read the Battlecorals led use, they are NOT using 350 Par. jus sayin. Radions @ 16 in white chanel only @ 100%. no ramp. mech timer

 

[mcarroll]

Not sure I've seen it...something they posted here?

 

[saltyfilmfolks]

Not sure I've seen it...something they posted here?

Arrg cant find it.....

 

[mcarroll]

Here? Lighting.....

Sounds like he's blasting his corals.....(his words on the website) but I didn't see any numbers....(yet)

 

[saltyfilmfolks]

Here? Lighting.....

Sounds like he's blasting his corals.....(his words on the website) but I didn't see any numbers....(yet)

yup that's the one. And by blasting, I believe he means using the higher levels the olds school guys(incl. the lighting manufactures I get to talk to on r2r) used and still insist on.

 

[mcarroll]

Just wish there were numbers associated.

I got into my whole mess going just by comments like that....

 

[mcarroll]

just posted there

 

[Centerline]

I run a tank with Hydra HDs and get good growth at 250 par. Same amount of par in a zone I have on a tank running Radium MHs gives much better growth. I'm sure its an issue with bits of spectrum missing between the peaks. So I'm not go crazy and crank the leds up all the way. They seems produce steady growth regardless but I run my a/c/m fairly high in both tanks. Lots of food and amino.

 

[mcarroll]

I run a tank with Hydra HDs and get good growth at 250 par. Same amount of par in a zone I have on a tank running Radium MHs gives much better growth. I'm sure its an issue with bits of spectrum missing between the peaks. So I'm not go crazy and crank the leds up all the way. They seems produce steady growth regardless but I run my a/c/m fairly high in both tanks. Lots of food and amino.

+1 to growing under low light!

But it's pretty hard draw comparisons I think.

This is why even spending $xxx on a meter, numbers are still just numbers.

For a fuller picture of the differences, instead of just comparing the readings of light coming from "up", we should probably take readings of the light from Up, Down, Toward the Front, Toward the Back (at least) from every location we sample. The corals do. But that's a level of complexity in measuring we're rarely if ever up to. It might even be hard to say if going there would be worth it, but it would enable better comparisons between your own systems at least.

Even though the Radiums and the Hydras may have shared a "downwelling irradiance" number from the lights directly, I bet the Radiums would have shown significantly higher readings from the walls of the tank.

 

[dave57]

I just came back from my LFS. The owner and I were discussing par values couple weeks ago as I wanted to know what levels he was running at. He became curious and I told him I had a par meter and That I would take it the following week. He keeps all types of corals under Kessil leds.. runs them at 50% intensity. I took my par meter with me surprisingly him and I were shocked to see the results. Literally every coral at his shop was below 120 par. Sps, lps, and softies were all alive and thriving at 40-120 par. He couldn't believe it and I was amazed . This finally proved to me that corals especially sps can maintain their beautiful colors and can thrive in such low par levels. I was shocked to see a red planet sps with such vivid color at 100 par.

 

[mcarroll]

@dave57 Could you please repeat that? I think repeating something as good as that is worth-while.

I've had a tank of stony corals growing under 10,000 lux at the surface...150-200 PAR. Stony's seem to grow fine even down on the sand.

(BTW, most folks claim that your meter is too conservative on Kessil lights.....not sure what their proof is so maybe someone will link some.....but even if your numbers needed to be 25% highter, that's only a difference of 125 and 150 PAR. 150 PAR is still L O W.)

 

[dave57]

@dave57 Could you please repeat that? I think repeating something as good as that is worth-while.

I've had a tank of stony corals growing under 10,000 lux at the surface...150-200 PAR. Stony's seem to grow fine even down on the sand.

(BTW, most folks claim that your meter is too conservative on Kessil lights.....not sure what their proof is so maybe someone will link some.....but even if your numbers needed to be 25% highter, that's only a difference of 125 and 150 PAR. 150 PAR is still L O W.)

Ya he was speechless and so was I. A lot of people can't accept the fact that sps can thrive in such (low) par levels. The minute I came home I lowered my light levels, and begun to acclimate my new red planet.

 

[saltyfilmfolks]

funny Right?
And at the same time. there's This.
https://www.reef2reef.com/threads/lighting.268204/page-2#post-3451741

 

[dave57]

funny Right?
And at the same time. there's This.
https://www.reef2reef.com/threads/lighting.268204/page-2#post-3451741

Ya that's crazy.. i still wouldn't blast my corals with 600 par unless I want them cooked.

 

[Broadfield]

I'm also a low PAR reefer. I have 13,000 Lux at the water and no more than 200 PAR anywhere in the tank. Honestly, if I turn it up much more than that, some of my corals get mad. I run a fairly low fish load and pretty low nutrients. I'm a firm believer of the correlation between the amount of nutrients available to the coral and the amount of light said corals can handle/need.

 

[dave57]

I'm also a low PAR reefer. I have 13,000 Lux at the water and no more than 200 PAR anywhere in the tank. Honestly, if I turn it up much more than that, some of my corals get mad. I run a fairly low fish load and pretty low nutrients. I'm a firm believer of the correlation between the amount of nutrients available to the coral and the amount of light said corals can handle/need.

That's awesome, have pics?