How to successfully keep SPS Corals!

[Velodog2]

For our purposes, lux - as interpreted by a cheap (or even free) meter - is just fine.

-Matt

The app available for the iPhone called Light Meter would qualify I think. I've compared it to an actual light meter and it is very close indeed. The ability of a camera such as on a decent phone to set exposures correctly is dependent on the quality of the light meter, so it has to be fairly good.

 

[Fishlee]

How much lux would be recommended / equivalent to par ratio

 

[Fishlee]

How much lux would be recommended / equivalent to par ratio

Is lux the same as iso

 

[ReefJeeper]

Ive been wanting to buy a submersible phone case and when i do i will report back my lux readings at various depths under my 250 mh and also what they are in par value at same depth using the light meter app on iphone for lux and an apogee par meter. Ultimately there just needs to be more data collection. via par meters, lux meters, threads such as this one with peoples succesful systems and their husbandry

Heres an article on converting lux to par.

Product Review: Lighting for Reef Aquaria: Tips on Taking Light Measurements ? Advanced Aquarist | Aquarist Magazine and Blog

They do also say that lux meters do not measure blue or red light well, and those are the most important for photosynthesis.

 

[mcarroll]

PAR meters are similarly calibrated...why they also misrepresent blue on our lights.

I really think there's very little difference between measuring in lux and par for us. Neither is scientifically very accurate unless you get a very high-end unit that's actually designed for your light source. We learn about the same useful info from either one as well. Cost (<$20 vs >$100) may be the biggest difference to us.

In any event I'm looking forward to your results!

-Matt

 

[mcarroll]

Is lux the same as iso

There may be a relationship but they are not the same.

-Matt

 

[ReefJeeper]

PAR meters are similarly calibrated...why they also misrepresent blue on our lights.

I really think there's very little difference between measuring in lux and par for us. Neither is scientifically very accurate unless you get a very high-end unit that's actually designed for your light source. We learn about the same useful info from either one as well. Cost (<$20 vs >$100) may be the biggest difference to us.

In any event I'm looking forward to your results!

-Matt

Unfortunately my sps dedicated system is just a year young and only now starting to be actually stocked.. so hopefully some more people chime in on what readings they are getting with their lux or par meters at the points of various healthy growing sps sp.

 

[ReefJeeper]

I dont have much acropora experience at all so im really here trying to learn. Ive had colonies of Montipora and Seriatopora for years growing great and colored great at ~180 par and ~250 par respectively.

I tested with a lux meter on my phone and 10" under my 250w pheonix 14k w/ lumenarc reflectors it tested ~26,000 LUX.
At that same height my apogee par meter read ~1000 PAR.

Right now i get a little over 200 PAR on my sandbed 24" deep tank.

im a big fan of minimalist aquascapes and negative space so i normally cant just put my acropora in the upper third of the tank like everyone else and call it dandy..

 

[ReefJeeper]

Heres an awesome article by dana riddle on compensation points and saturation points of light intensity for various sp.

He also has several articles on coral coloration and its relation to light intensity worth reading.

Long story short he shows that these corals arent growing any faster at light intensities above 350 par

Feature Article: How Much Light?! Analyses of Selected Shallow Water Invertebrates' Light Requirements ? Advanced Aquarist | Aquarist Magazine and Blog

 

[ReefJeeper]

Another good article, If you scroll down theres a par vs lux section

Testing 250-watt Single-ended Metal Halide Lamps and Ballasts by Joe Burger - Reefkeeping.com

 

[mcarroll]

Someone is welcome to add more detail or corrections for my PAR numbers, but here's an interesting comparison.

From the number (and link) in post #247, 350 PAR is about 17% of peak direct sunlight - which I understand to be about 2000 PAR at sea level.

This percentage isn't completely surprising if you have been paying attention to lux measuring.

130,000 lux is peak direct sunlight as I understand it. 17% of that is about 22000 lux - or about regular full daylight levels.

So corals are best-adapted to regular full daylight. It took all of science and a new unit of light measurement (PAR) to figure that out? Huh.

This is why (again, repeat) measuring in lux is fine for us.

All we really have to do is make sure we're around the full-daylight range....and probably make sure we don't get too close to direct sunlight numbers. This is a lightweight task that is not a problem to do with a lux meter. The correct range is very wide, so additional accuracy isn't really needed.

-Matt

P.S. FWIW, Dana says "300 PAR" as well as "400 PAR or less", instead of 350 PAR as the ideal peak for corals in this article: Feature Article: Imitating Natural Light Quality, Intensity, and Dosage in a Reef Aquarium - Do We Really Want To? ? Advanced Aquarist | Aquarist Magazine and Blog Not a huge discrepancy, but might give the idea that there's a range rather than just one correct number.

 

[ReefJeeper]

Not trying to argue about which units one should measure light in, just posting relevant information. Im only interested in some sort of data from other succesful aquarists as i stated before. Par, lux, doesnt matter. 350 was a rough number referring to the average saturation points for listed sp. in study.. Just a ballpark number to keep in mind that several sp. wont utilize more par than this. Actual scientific data on growth rates and its relation to light intensity is worth its weight in gold if you have the ability to use it.

Someone is welcome to add more detail or corrections for my PAR numbers, but here's an interesting comparison.

From the number (and link) in post #247, 350 PAR is about 17% of peak direct sunlight - which I understand to be about 2000 PAR at sea level.

This percentage isn't completely surprising if you have been paying attention to lux measuring.

130,000 lux is peak direct sunlight as I understand it. 17% of that is about 22000 lux - or about regular full daylight levels.

So corals are best-adapted to regular full daylight. It took all of science and a new unit of light measurement (PAR) to figure that out? Huh.

This is why (again, repeat) measuring in lux is fine for us.

All we really have to do is make sure we're around the full-daylight range....and probably make sure we don't get too close to direct sunlight numbers. This is a lightweight task that is not a problem to do with a lux meter. The correct range is very wide, so additional accuracy isn't really needed.

-Matt

P.S. FWIW, Dana says "300 PAR" as well as "400 PAR or less", instead of 350 PAR as the ideal peak for corals in this article: Feature Article: Imitating Natural Light Quality, Intensity, and Dosage in a Reef Aquarium - Do We Really Want To? ? Advanced Aquarist | Aquarist Magazine and Blog Not a huge discrepancy, but might give the idea that there's a range rather than just one correct number.

 

[ReefJeeper]

What are your lux values at the waters surface matt? How deep of a tank? And how do acropora sp. do for you? You are correct this doesnt have to be rocket science, just need to know whats been working for everyone else and add it to our data pool.

 

[Greenstreet.1]

Well don't know if this will help but took these today. These are my t5 readings LEDs where off already will do one with the LEDs tomorrow. These readings where taken from three different spots over some of my best growers with iPhone free lux app.
Position 1: lux 15951
Position 2: lux 14776
Position 3: lux 13111

 

[Greenstreet.1]

These are from today with LEDs
Lux 6089
Lux 16026
Lux 15761

 

[ReefJeeper]

Well don't know if this will help but took these today. These are my t5 readings LEDs where off already will do one with the LEDs tomorrow. These readings where taken from three different spots over some of my best growers with iPhone free lux app.
Position 1: lux 15951
Position 2: lux 14776
Position 3: lux 13111

Thank you for the information..
Was this using a submersible case or were these values at the surface?

 

[mcarroll]

I see what you mean, but I don't think I meant that to sound so argumentative...LOL. I actually wasn't replying directly to anyone/anything. Just being a bit emphatic to make the point of how simple this really can be. You got it.

No acros growing currently, but they did well in the past with similar lux numbers. (I'm really a Monti. nut. FWIW, mushrooms did in my Green Slimer via encroachment. He grew like a weed, but still not fast enough.)

Thought I had already posted lux numbers in this thread. I've been meaning to take some new readings just to refresh my memory anyway....will see if I can remember tomorrow...

-Matt

 

[mcarroll]

I see what you mean, but I don't think I meant that to sound so argumentative...LOL. I actually wasn't replying directly to anyone/anything. Just being a bit emphatic to make the point of how simple this really can be. You got it.

No acros growing currently, but they did well in the past with similar lux numbers. (I'm really a Monti. nut. FWIW, mushrooms did in my Green Slimer via encroachment. He grew like a weed, but still not fast enough.) FWIW, I'm getting excellent growth in two different M. digitata frags (volunteers, really) that are on the bare bottom (18" down) of my 50 gal.

Thought I had already posted lux numbers in this thread. (Oh! Different thread.... Try here. Back then I read 65,000 lux around my lights' hot spot.) I've been meaning to take some new readings just to refresh my memory anyway....will see if I can remember tomorrow and post them here...

Also, please continue reporting lux measurements at the water surface (but don't get your phone wet! close is good enough!), and include the height of your lights off the water.

Below the surface there is essentially infinite variability in terms of what a coral would really "see" underwater due to angle of placement, growth, surface waves, et al...so instead of trying to account for all these variables you can estimate by math just about as well using your surface measurements. (But you really shouldn't need to....if you're in range according to surface measurements, according to the laws of physics the rest is in range too. We can trust our corals to act accordingly at this point.)

-Matt

 

[Greenstreet.1]

These where at the surface

 

[ritter6788]

I'm not scared to admit I use a lux meter. I use a Milwaukee lux meter with a submersible sensor. It's great. I have several acros growing well in my tank so I can measure the amount of light they are getting and know where to best place my new corals.

It was really handy when I got a new maxspect razor and I dimmed the light to match the brightness of my other non-dimmable LEDs that were growing sps well.