How to find your LED Intensity Sweet Spot??

[Shaun Sweeney]

I like the "canary" idea and I'm busy trying to figure out who the canary will be. Meanwhile, I use older Radios and I run one of the optional pre programmed profile. Over the past few months, I've dialled them up to 100% and thinks seem ok. My tank is deeper than most at about 32".

 

[Sharvey103]

I have 4 G3 radions over a 300DD sps dominant tank and run at 65% intensity. Great growth and colors using the right balance of additives.

 

[OverHauler]

Following...

 

[sebastiaan1985]

Currently I am rebuilding my 40gallon tank. Before I add any corals, I will use my PAR-meter to find the 'theoretical' sweet spot and maximum intensity.
During cycling, I will dial this down and keep it lower while first corals are introduced (after QT).

When I have added some more corals, I will slowly raise intensity towards the 'theoretical' maximum and see coral response. Intensity will be increased by 1% every second day during intensity increase. Acclimation will take about a month.
Newer corals will get acclimation during their month in QT (looking to get similar lighting for my QT, so anybody a XR15 G3 for sale?)

 

[NickK]

Read this if you haven't already.

http://ecotechmarine.com/wp-content/uploads/2016/01/Ecotech_CoralLab_WP1.pdf

I have a G3 XR30 Pro on an RMS mount. I run AB+ at 70% and I question if that is too intense.

Those G4's have a better spread so I would guess you could run them at a higher intensity than the G3's. The height of the fixture is a big consideration. Ideally, I wish my G3 were mounted higher, but I like the way the RMS mount looks. Find someone that is running your same fixture, height, and schedule successfully and that will give you a target to aim at.

 

[editour2]

I have been running LED fixtures over my tank since Nov 2011. I started out with 3 x Reef-tek fixtures (now out of business). These fixtures only had 3 colors/channels...those being Cree Cool White (6500 to 8500 range), Cree Royal Blue and Cree Blue. Each fixture has 60 3 watt LEDs. I slowly ramped up the intensity over a period of time to 85% on both Blues and 35% for the white.....In 2014 I added 4 x 80w T-5's because the color spectrum provided by these fixtures were not adequate. As my corals grew some at the top of my rockscape began to show burning tips.....these were my acros, (red planet, blueberry). I decided to lower the intensity specifically on the whites to 25% and the burning stopped. I also lowered the blues to 80%. I believe trial and error is the only way to find the sweet spot AND each tank will have a different sweet spot. My tank is 24" deep with a 6" sand bed.

 

[Larry L]

It funny i was reading that wwc runs pretty low par settings on there main grow out tank.

The SPS aquaculture run using AI Hydra lighting receives PAR exposure in the 250-275 range, the LPS and Deep Water corals under the T5 lighting receives 80-140 PAR."

They certainly aren't blasting anything.

its low par for long duration. Ie extended DailyLightIintegral.

Dana Riddle has published a fair amount of research showing that photosynthesis maxes out right about in that mid-200s range (at least for the types of corals he is looking at, usually Porites), so with respect to growth you aren't gaining much (if anything) by going over that.

As @saltyfilmfolks already mentioned, Google for Dana Riddle and "daily light interval" to find some really good articles. His MACNA 2016 presentation (on YouTube) about the effects of lighting, flow, and alkalinity on coral growth is also well worth watching.

 

[saltyfilmfolks]

photosynthesis maxes out right about in that mid-200s range (at least for the types of corals he is looking at, usually Porites),

+1
350 par in the priorities.
Really it then raised my questions about "low light" corals.

 

[SashimiTurtle]

I've heard a lot that par isn't an accurate way to measure LEDs. Especially Kessil LEDs. I believe the company has even said that meters will underreport PAR. Anyone know if there is an accurate measurement for LEDs?

 

[saltyfilmfolks]

I've heard a lot that par isn't an accurate way to measure LEDs. Especially Kessil LEDs.

Sorry if this sounds harsh, but yes that has been their official stance. They have actually reported it cannot be used on their light. The is NO scientific data to suggest this is true. One has to be able to quantify the amount of of light a fixture produces. In lumens, lux, foot candles, or Par. They refute all these facts.
By their logic an a 160 should be fine on a 36in deep tank, yet they don't recommend it. So one would wonder how or why they would recommend a larger light.

As a skeptic and lifelong lighting guy , (and lifelong skeptic) ,yea I do think a par meter is a bit misleading in a way for pretty technical reasons, But it really is the test we do have.

 

[SashimiTurtle]

Sorry if this sounds harsh, but yes that has been their official stance. They have actually reported it cannot be used on their light. The is NO scientific data to suggest this is true. One has to be able to quantify the amount of of light a fixture produces. In lumens, lux, foot candles, or Par. They refute all these facts.
By their logic an a 160 should be fine on a 36in deep tank, yet they don't recommend it. So one would wonder how or why they would recommend a larger light.

As a skeptic and lifelong lighting guy , (and lifelong skeptic) ,yea I do think a par meter is a bit misleading in a way for pretty technical reasons, But it really is the test we do have.

I am a bit skeptical of the "Kessil PAR meter claim" also. Photons are photons as far as I've read. They may be arranged in different wave lengths, but they are the same pieces of matter none the less. I've also read that PUR is far more important than PAR.

 

[saltyfilmfolks]

I am a bit skeptical of the "Kessil PAR meter claim" also. Photons are photons as far as I've read. They may be arranged in different wave lengths, but they are the same pieces of matter none the less. I've also read that PUR is far more important than PAR.

yup, you got it!
And par is even more complicated and harder to measure IMO.

 

[Stolireef]

Just thought I'd mention nice new avatar, although I miss Stoli...

I couldn't find the picture of Stoli that I used on RC. It's probably 15 years old.

Then again, Bentley Reef just doesn't have the same ring to it as Stolireef.

 

[Stolireef]

It's interesting. I've been corresponding with a few of the high end coral vendors that use LEDs. Almost all of them have shallow 'run' tanks for their frags and they all seem to blast them with light. Cultivated Reef is running Radion G4's at 100%. Battle is similar. And they run long photo-periods.

My working hypothesis is that a heavily fed tank with excellent nutrient export can be run with much higher intensity lighting. We've all seen the nutrient threads but I think most of them fail to consider that just because you have undetectable nutrients, it doesn't mean they aren't in the water column. What it may mean (and I have do not have the bio-chemistry chops to prove this) is that the corals and other nutrient export mechanisms are at some kind of balance with the import of the nutrients into the tank. Probably a bad analogy but it reminds me a little of dosing Ca/kH where the corals take them up at the same rate that you dose them.

With the foregoing in mind, I'm going to continue to feed on the heavier side, grow chaeto like crazy, and gradually up the lighting (I'll keep a very close eye out for nuisance algae and will take weekly nitrate measurement for piece of mind). I'd like to see what happens if I get to 100% intensity.

 

[Scott.h]

Sorry about the 'snark' comment. The smiley face was supposed to be after it. I really did think it was funny. I have a friend who is what I consider a master running a huge (750 gallons) tank and he is running the original AI Blues and Whites at 30%. Coral color is amazing and they grow out of the top of his tank. That's why I was surprised at Sanjay's intensity.

Its all about the relationship. His tank has nitrates in excess of 50. His kh is also high. The light intensity matches the other parameters. If one of the 3 (4 actually as po4 plays a roll too) is out of align it creates an issue. Cranking light to a coral to get it to grow when there is no food source creates a problem. So his tank is so packed with corals sucking up those nutrients, algae is not a problem either. Cool stuff

 

[Eric Tang]

This is a very interesting topic but I think it is very difficult to have a single correct answer as the sweet spot depends on a lot of factors like coral species, water chemistry, water flow, age of the tank, and etc. I have actually watched this video from BRS and will agree with the speaker that dKH plays an important together with lighting intensity. Actually, we had been putting too much emphasis on the light output of lighting fixtures but it has proven that the output is not the single best answer to have good coral colors/growth.

I will be honest, part of this message is to explain the feature of our new light but I think with our moving angle feature you can have several sweet spots for your single LED fixture rather than only 1 sweet spot for a normal non-moving LED light (not brand specific). Our moving feature not only provide a visual effect but actually allows you to put out higher PAR over longer period of time because there will not be a single "hot spot" that may burn your corals within that couple of inches of area.

 

[saltyfilmfolks]

This is a very interesting topic but I think it is very difficult to have a single correct answer as the sweet spot depends on a lot of factors like coral species, water chemistry, water flow, age of the tank, and etc. I have actually watched this video from BRS and will agree with the speaker that dKH plays an important together with lighting intensity. Actually, we had been putting too much emphasis on the light output of lighting fixtures but it has proven that the output is not the single best answer to have good coral colors/growth.

I will be honest, part of this message is to explain the feature of our new light but I think with our moving angle feature you can have several sweet spots for your single LED fixture rather than only 1 sweet spot for a normal non-moving LED light (not brand specific). Our moving feature not only provide a visual effect but actually allows you to put out higher PAR over longer period of time because there will not be a single "hot spot" that may burn your corals within that couple of inches of area.

What are you even talking about? A light needs to move to stop from burning it?