Looking for a used par meter

[Scott.h]

Is this all I'll need to successfully dial in LEDs? Or would par still come into play?

http://www.testequipmentdepot.com/products.htm?item=MW700&ref=gbase&gclid=CMPNhI_poMsCFZA2aQodeh8K7g

 

[mcarroll]

The reality is that measuring light - especially in water - in pretty much an infinitely complex proposition.

So, I try to take the simplest approach that yields results.

In this case, that means, I set the lights up how I like them in terms of "color" (how blue, how white, whatever) and then use the lux meter to take that light to the preferred intensity.

It can be that simple. It does work.

(We primarily have the adaptability of corals to thank for the facts that our unrealistic lights and inaccurate light meters do the jobs for us at all - but they do! Within pretty wide limits, corals are very adaptable.)

 

[mcarroll]

Yes, that meter is fine.

I would only restate that testing beneath the water's surface is "extra".

At $15 for the plain lux meter vs $56+shipping for the waterproof one it may be worth it even if just to satisfy the curiosity.

Just don't feel like there's any requirement for the measurements to be taken underwater - measurements at the surface are sufficient.

 

[Greenstreet.1]

I have 2 hydra 52 10" above a 75g how much lux should my starting point or how much lux should I be looking for ?

 

[mcarroll]

I can depend on the corals and rock work, but in general 40,000-50,000 lux is a good target.

(Less can be fine. More is not better. 20,000-80,000 lux seems to be the safe range.)

 

[Greenstreet.1]

Ok will see where I'm at tomorrow 52's are off but will see what I get from my t5

 

[Scott.h]

Yes, that meter is fine.

I would only restate that testing beneath the water's surface is "extra".

At $15 for the plain lux meter vs $56+shipping for the waterproof one it may be worth it even if just to satisfy the curiosity.

Just don't feel like there's any requirement for the measurements to be taken underwater - measurements at the surface are sufficient.

ok noted. Thanks for the help. At 56 dollars I feel like it's a steal. That's less then I planned on paying for a used par meter. It makes me wonder how come par meters cost so much more.

I have it coming. So just so I understand, lux shouldn't lose numbers from the bottom of the tank to the top, or is there a formula for distance?

 

[sc50964]

I can depend on the corals and rock work, but in general 40,000-50,000 lux is a good target.

(Less can be fine. More is not better. 20,000-80,000 lux seems to be the safe range.)

How about LPS? How much lux is needed?

 

[saltyfilmfolks]

I can depend on the corals and rock work, but in general 40,000-50,000 lux is a good target.

(Less can be fine. More is not better. 20,000-80,000 lux seems to be the safe range.)

And @ 50,000 that can be considered high and is a target for the top of the tank. Using a conversion of 14k metal halide that's around 600 or 700 par.

That's high. At those levels it's good to look into a par meter or proceed cautiously esp depending on the depth of the tank and distance to the nearest coral.

The research from coral to coral as to what light it likes does not change. But now high medium and low is quantified buy a number. In lux or par and now you have a reference to go by.

And again if I read the scientific research correctly 350 par is fine as a high mark. So high is 500 or more and should be approached cautiously for the average user.

I.e. The average user does not read the scientific research that is well published on the Internet.

 

[saltyfilmfolks]

ok noted. Thanks for the help. At 56 dollars I feel like it's a steal. That's less then I planned on paying for a used par meter. It makes me wonder how come par meters cost so much more.

I have it coming. So just so I understand, lux shouldn't lose numbers from the bottom of the tank to the top, or is there a formula for distance?

Once you get the meter in your hand it's quite simple.
The farther away from the light. The less you read. Calculate from there.

Form source to source there is some difference in fall off But from only 12 to 20!in its negligible.

I have to calculate photo metrics of instruments regularly in yards an miles with some light sources.

Light in aquaria sadly has become over mystified. It is very very simple. It's easier than carbon dosing that's for sure.

Btw
Par meter cost more as they have a highly calibrated optical system to refine and separate the spectrum over the photocell and a software calculator.

And when the say lux meter doesn't do well in blue it's a pretty small amount scientifically speaking.

 

[saltyfilmfolks]

How about LPS? How much lux is needed?

How much par is needed?

 

[sc50964]

How much par is needed?

150 par under a kessil a350w. Trying to figure out how close it needs to be to the LED. Thanks.

 

[mcarroll]

How about LPS? How much lux is needed?

You should look up the specific coral you have in mind to see if it is noon to come from a specific environment or if it's a generalist a coral appears everywhere. For example, some LPS are someone specific to lagoons. That could imply brighter light, less blue and more red light, as well as a more turbid environment. On the other hand, many corals are generalists and are found in all reef environments. Others are more exclusive to deep water. Because there is so much overlap between corals and their adaptability, 40,000 to 50,000 makes a great target point for your lights.

 

[sc50964]

You should look up the specific coral you have in mind to see if it is noon to come from a specific environment or if it's a generalist a coral appears everywhere. For example, some LPS are someone specific to lagoons. That could imply brighter light, less blue and more red light, as well as a more turbid environment. On the other hand, many corals are generalists and are found in all reef environments. Others are more exclusive to deep water. Because there is so much overlap between corals and their adaptability, 40,000 to 50,000 makes a great target point for your lights.

Thanks. I am looking to get the proper lighting for meat coral, or acanthophyllia. My research has shown that it needs 50 to 150 par. I downloaded the lux meter onto my iPhone and am getting the $15 lux meter today. I found an online link that gives the following equation for blue/white LED.

lux/67 = par

But that just seems too simple to me and my current lux reading from my iPhone app seems to suggest that my a350w isn't powerful enough even at the water surface which is 12" away from the light source.

That's why I'm seeking for another set of eyes for what I'm looking for.

Thanks.

 

[saltyfilmfolks]

Thanks. I am looking to get the proper lighting for meat coral, or acanthophyllia. My research has shown that it needs 50 to 150 par. I downloaded the lux meter onto my iPhone and am getting the $15 lux meter today. I found an online link that gives the following equation for blue/white LED.

lux/67 = par

But that just seems too simple to me and my current lux reading from my iPhone app seems to suggest that my a350w isn't powerful enough even at the water surface which is 12" away from the light source.

That's why I'm seeking for another set of eyes for what I'm looking for.

Thanks.

yea no sweat. me too. been researching the prob HARD the last 6 or 8 months

Google advanced aquarist led lux conversion dana riddle has answers. your going advanced there.

But simply, knowing you have a good quality lamp at a set intensity your really good to go.
in the advanced its hard to balance leds esp with the advanced spectral adjusability.

And yea its actually that simple too. if you take 40,000 lux at the top of the water and devide it by the conversion factor, thats your answer. it really is.
look at the MH conversion table and do that math.do the other conversion factors too. it really does work out and is backed by real research. By Dana Riddle.
And to make it more simple, corals are pretty adaptable.
knowing around where you Par/lux is, is just another parameter.

and yea 67 seems odd. what link are you using?

 

[Greenstreet.1]

Ok so just got home and did a test with the Galactica iPhone app and I got 92.2k hydra 52x2 and ATI 4x54w

 

[mcarroll]

lux/67 = par

But that just seems too simple to me

That's about it....the 67 is due to the color differences of a particular LED fixture (or halide/T5 bulb) from sunlight.

If you're just talking about sunlight "generically" the math is simple...these are all equal:

• "direct sunlight" at sea level
• 100,000 lux
• 2000 PAR
• 1000 watts/square meter

And honestly, I don't even try to be more accurate than these simple conversions. It works. 100,000 lux / 2000 PAR = 50 That's nice, easy math.

That said, if you have a lux meter and a PAR meter at the same time, that's how you make a conversion factor.

Once you know one equivalent measurement for your light from both meters, you have a valid conversion factor for all future lux measurements. Realizing that kinda de-mystified PAR for me.

But don't let this be anti-PAR-meter....use whatever meter you can get your hands on. A PAR meter will techincally be more accurate by some percentage (see: conversion factors) but a lux meter is not so inaccurate to be useless.

It works just find for this purpose: Shoot for around 40,000 lux - anywhere in that vicinity - and your corals should be happy.

The "complete range" for for corals - should you want a "shallow water" or "deep water" environment for example, is from around 20,000 lux to 80,000 lux. Inside that range seems safe for most corals. Some corals do fine above and below that range, but be watchful if you're using that much/little light for the first time...it can definitely stress corals.

 

[sc50964]

yea no sweat. me too. been researching the prob HARD the last 6 or 8 months

Google advanced aquarist led lux conversion dana riddle has answers. your going advanced there.

But simply, knowing you have a good quality lamp at a set intensity your really good to go.
in the advanced its hard to balance leds esp with the advanced spectral adjusability.

And yea its actually that simple too. if you take 40,000 lux at the top of the water and devide it by the conversion factor, thats your answer. it really is.
look at the MH conversion table and do that math.do the other conversion factors too. it really does work out and is backed by real research. By Dana Riddle.
And to make it more simple, corals are pretty adaptable.
knowing around where you Par/lux is, is just another parameter.

and yea 67 seems odd. what link are you using?

http://www.advancedaquarist.com/2013/2/equipment

 

[mcarroll]

Ok so just got home and did a test with the Galactica iPhone app and I got 92.2k hydra 52x2 and ATI 4x54w

Sounds probable.

What readings do you get around the tank edge? How about readings from half way to the edges?

 

[Greenstreet.1]

45-52 k