Lux range for SPS reef tank

[crcleb1993]

Hello all.
Don't know if this is for the right forum but what is the ideal Lux range for a SPS reef tank ? I'm 21" top waterline to sand bed.

 

[mcarroll]

That's only a complex question if you think about it too hard.

The answer is "full daylight" to "direct sunlight" levels.

Roughly, between 30,000 and 80,000 lux.

When you are measuring (vs guessing using your eyeballs) and trying to hit a specific target lighting level, the first thing you notice is that it's actually a very large, easy target to hit.

And there's no need to fixate on the high-end of the target necessarily. Most of us are actually trying to set up a deeper water lighting environment, not a near-surface environment.

Wikipedia's article on lux has a complete index of common lighting levels, FYI.

 

[saltyfilmfolks]

Look at Dana Riddle articles. He starts one article by doing exactly that. It's pretty complex actually and achieving 80,000 lux is pretty hard to do. If you know how or have done it please let me know.
By your question I assume you have the meter. I spent 2 days looking at old 2001 threads this week and found enough to believe that 3000 Lux on the sandbed is a good starting point. I measured my 55 mixed that's doing well with Zoas on the bottom to half way up. The bottom measured about 1300 to 1900. With 4 power compacts in a standard 55g
My jbj nano 28g at the bed was 3000. Awful spectrum though.
The par Lux conversion seems pretty off. Maybe I did it wrong or my corals are dead.
I'm using this 3000 Lux point for my MH tomorrow.
Honestly if all light manufactures would use lux @ distance as a starting point it would be easier to choose a light.
But then they would sell less junk.
And we would stop using highly technical terms like High med and low light.

 

[saltyfilmfolks]

Hello all.
Don't know if this is for the right forum but what is the ideal Lux range for a SPS reef tank ? I'm 21" top waterline to sand bed.

And measure lamp to bed. Not rim. It actually makes it easier because you can do it dry by holding the light. If it's led. Set to 80% and measure 21in to the floor. Now you know how high the fixture need to be. + 20% if you need or want it later. Or what intensity it need to be at if you already have a mount.

 

[mcarroll]

Lux measurements are taken at the planet's surface, not underwater.

You should do the same and measure at the water's surface.

My Razor lays out >80,000 lux on my 50 gallon.

My DIY rig only hits about 25,000 lux over the 40 gallon.

FWIW, both grow the same corals (SPS mostly) equally well. [emoji106][emoji41][emoji3] (I'm sure growth rates are different, but not so much I can tell by casual observation.)

 

[mcarroll]

(if you are trying to reproduce Dana's experiments, it's a different story. But if you're trying to light your tank you do so the way I described. [emoji6])

 

[saltyfilmfolks]

Lux measurements are taken at the planet's surface, not underwater.

You should do the same and measure at the water's surface.

My Razor lays out >80,000 lux on my 50 gallon.

My DIY rig only hits about 25,000 lux over the 40 gallon.

FWIW, both grow the same corals (SPS mostly) equally well. [emoji106][emoji41][emoji3] (I'm sure growth rates are different, but not so much I can tell...)

Totally been waiting to find someone like you. I have only found threads from the old schoolers. Im not trying to be snarky but soo many chime in who dont own a meter and I honestly want to learn more.
your 80k is at the waters surface? how far from the unit? And I assume that's averaging over the top plane of the tank, with a single point flat disk meter?

I have used lux in photographic exposure for decades regardless of location. its a standard like footcandles.

 

[saltyfilmfolks]

And yea im at 12k + lux on my softies at the top. I think were both right. MR Riddle does also say corals are pretty adaptable.

 

[mcarroll]

Ideally your tank's and light's geometry will be what dictates mounting height, minimizing both spill and dark corners. Dimming will control brightness.

My DIY fixture lights 100% of the tank space while spilling so little light that I only scrape the glass once a year or so.

The tank with the Razor (which is part of the same system) needs to be scraped monthly.

That is not a knock against the razor, as it's largely designed the same as most of the commercial fixtures. It's just to point out that the design and setup of LEDs can be very precise if you let it.

 

[mcarroll]

Ya I use a standard digital lux meter. $15-$20 seems to be a reasonable cost. 80,000 is the peak for my light settings, as measured with the sensor straight up and as close to the water surface as comfortable, and which I've recently dialed back.

Unless you're trying to generate a surface environment ("reef crest", etc) there's no real reason to target the high end of the preferred range. Anything from 20,000 to 80,000 is going to be widely acceptable. May as well shoot up the middle and tweak it from there IMO. Chances are the corals won't care and you will save power. [emoji106][emoji6]

 

[saltyfilmfolks]

My gripe on any/all lighting is not having a good set standars. Or at least on thats easy to understand be intermediate users. Lux and distance are pretty simple to formula.
IE This Light produces 80k @ 6in 40k@12in etc. New higher end do give better 3d modeled par graphs. But a LFS cant quanitfy what amount of light for a tank. Oy

So thanks for chiming in. Its best to have someone else ACTUALLY doing it to ask.
Have you metered at depth dry? what did you think bout the method Im using. for dry testing.
I did it because tank depth differs greatly and seting the bottom first would allow a low spot(I do have 20% power in reserve) for lower light corals. and let the grade go up to about yea 40k.(ill meter again)@20in
And it was the only info I found.
How did you figure out the 40 to 80K?

 

[mcarroll]

Measuring the light levels beneath the surface may be interesting in other scenarios, but here's why I don't bother and still successfully set up lights. (Bear with me...)

Space beneath the water surface in your tank is exactly like the space beneath the water surface in the ocean, including the large degree of randomness due to the wave action at the top. This "sameness" lets me just cancel this space out of the equation. Like a common denominator. [emoji3]

This is why I take my measurements at the water surface and am happy with that. I can completely assume what's going on beneath the surface and be fine.

In other words, if I have daylight levels of lighting above the water, I can be confident that the right thing is happening below the water. (We're almost always dealing with less than three feet of water...usually less than two feet...so this helps.)

My tanks (both of them) have been successfully running for four years or so with me designing and setting up lights this way, so take it for what it is. [emoji6]

 

[mcarroll]

People measuring lights below the surface are often trying to ascribe preferable light levels to particular corals.

Without commenting on that any further, I'll just say I'm not interested in that - just in having the proper light levels for my corals. Unless you have that reason or some other for specifically wanting to know the light level at a particular spot in the tank, my way should work fine for anyone.

(OK, I will comment a little further. [emoji56] I do not believe in corals needing levels of light that are that optimized. They are extremely adaptable creatures.)

 

[saltyfilmfolks]

I'm taking it as really good advice thank you very much.

Do you do the same for softie/ or Zoa. Or is your approach SPS primarily? Im assuming sps although I know Zoas live at varying depths and are adaptable.

If its different where would you start a ZOA dominant tank?

 

[saltyfilmfolks]

People measuring lights below the surface are often trying to ascribe preferable light levels to particular corals.

Without commenting on that any further, I'll just say I'm not interested in that - just in having the proper light levels for my corals. Unless you have that reason or some other for specifically wanting to know the light level at a particular spot in the tank, my way should work fine for anyone.

(OK, I will comment a little further. [emoji56] I do not believe in corals needing levels of light that are that optimized. They are extremely adaptable creatures.)

I concur fully.

(you type faster than me clearly)

 

[mcarroll]

I'm taking it as really good advice thank you very much.

Do you do the same for softie/ or Zoa. Or is your approach SPS primarily? Im assuming sps although I know Zoas live at varying depths and are adaptable.

If its different where would you start a ZOA dominant tank?

I think the same, but zoa's were never my thing.

I always found them to be much more touchy than stony corals - inexplicably so. I grew stony corals until there was no room left in the tank, but never did figure out what made the zoa's in there (gorilla nipples) happy or not. LOL

Still, they thrive in the wild under the same sun as the rest of our corals. [emoji6]

I think starting your lights "low" - say 20K-50K lux - and increasing only as needed from there (or not at all) makes even more sense if you've any question about a particular coral being sensitive.

 

[saltyfilmfolks]

Thank you. Great Thread.

 

[mcarroll]

I misspoke when I said my Razor gets up to 80,000 lux. Mid to high 50 K's is about it.

The sentiment still stands: even that is too much light. [emoji6]

At the peak of the daily cycle I only run the fixture at about 80% of its max which I am guessing it is in the 40,000 lux range. I need to take a fresh sample some time. [emoji6]

 

[kmog]

Look at Dana Riddle articles. He starts one article by doing exactly that. It's pretty complex actually and achieving 80,000 lux is pretty hard to do. If you know how or have done it please let me know.
By your question I assume you have the meter. I spent 2 days looking at old 2001 threads this week and found enough to believe that 3000 Lux on the sandbed is a good starting point. I measured my 55 mixed that's doing well with Zoas on the bottom to half way up. The bottom measured about 1300 to 1900. With 4 power compacts in a standard 55g
My jbj nano 28g at the bed was 3000. Awful spectrum though.
The par Lux conversion seems pretty off. Maybe I did it wrong or my corals are dead.
I'm using this 3000 Lux point for my MH tomorrow.
Honestly if all light manufactures would use lux @ distance as a starting point it would be easier to choose a light.
But then they would sell less junk.
And we would stop using highly technical terms like High med and low light.

 

[saltyfilmfolks]

sweet. Ill be checking it out against me meters!!