Help! - Am I getting my lighting Maths correct?

maj74

Member
Joined
19 Oct 2008
Messages
72
Trying to work out if I am purchasing enough light for my new 80 x 40 x 45 cm planted tank.

Will be well planted and will want to get good carpeting on the bottom with CO2 injection via an inline diffuser.

Am purchasing an Aquaray Grobeam 600 Duo (2 bars, 10 LED's) as I already have the controller from a previous tank.

I have used this calculator: https://rotalabutterfly.com/light-calculator.php

Please can someone check I'm interpreting things correctly using the supplied product info?

It looks like I should get around 68 PAR at the substrate which rates as high light, so can use the dimmer controller to exactly manage the level I want.

Am I correct?!!!

Thanks in advance.

Aquaray 600 Grobeam Product Info:


Uses the latest generation Natural Daylight 5 x CREE XB D Natural Daylight LED
Specified at 6500K for optimum plant growth and colour rendition.
Creates a natural shimmer effect.
120 degree wide angle beam allows light unit to be mounted close to the aquarium surface for optimum and even light distribution.
Perfect for planted tanks and tropical aquariums.
Offers a minimum of 50,000 hours lamp life 5 x standard fluorescent lighting.
Low running costs and environmentally friendly long life, very low carbon footprint and NO MERCURY.
Cool running with low heat transfer to aquarium water reducing the need for expensive cooling systems.
Light weight and compact design, with versatile mounting fixtures included, allowing a wide variety of replacement, retrofit and new install options on all sizes of aquaria.
Sealed, water resistant casing and a low voltage DC power supply makes AquaRay easy and safe to use in all conditions.
61 PAR at 400mm in air
only 12W Total power consumption at 700mA
86 lm W Efficacy
1029 Total Lumens

tank light 1.jpg


tank light 2.jpg
 

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maj74

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Joined
19 Oct 2008
Messages
72
Thanks for the reply. Not sure what that's telling me?! Lighting seems to be a confusing area!

If the tank in post 7 used 1 light and achieved a reading of 35 at 40cm above the substrate, then with 2 I should get around 70 yes? This seems to tie in with the calculator above.
 

oreo57

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19 Jun 2020
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81
Location
USA
Sorry, missed the 2x's part. My bad.
Anyways supporting documentation I suppose.

I have a very minor distrust of that calculator to be honest but seems to be in the ballpark here.

Long story.
 

zozo

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16 Apr 2015
Messages
7,415
Location
Netherlands
Lighting seems to be a confusing area!

It is... :) And the deeper you dive into it the more confusing it gets. Basically it's a trial and error concept.

Without any darn expensive electronic equipment to do the measurements to know where you're at, the only thing you have are the specs the vendor gives you... How these theoretical factory specs relate to your particular situation is a guess because there are a number of (unknown) variables at play. Factory specs don't tell you in what situation and how it was tested to come up with that number.

You would need an instrument like the Apogee MQ 500 with a waterproof sensor and this is around $700 likely more expensive than the entire aquarium setup. Then you need to know what you are reading and it still doesn't tell you all... :)

But for instance, you could follow this diagram according to LUX/LUMEN to vaguely determine if you are in the high, medium or low range.


What it means and how it works in reality is again a guess and something to find out along the way.
Only experience can tell you if you are on the correct path... :cool:

o_O
 

maj74

Member
Joined
19 Oct 2008
Messages
72
It is... :) And the deeper you dive into it the more confusing it gets. Basically it's a trial and error concept.

Without any darn expensive electronic equipment to do the measurements to know where you're at, the only thing you have are the specs the vendor gives you... How these theoretical factory specs relate to your particular situation is a guess because there are a number of (unknown) variables at play. Factory specs don't tell you in what situation and how it was tested to come up with that number.

You would need an instrument like the Apogee MQ 500 with a waterproof sensor and this is around $700 likely more expensive than the entire aquarium setup. Then you need to know what you are reading and it still doesn't tell you all... :)

But for instance, you could follow this diagram according to LUX/LUMEN to vaguely determine if you are in the high, medium or low range.


What it means and how it works in reality is again a guess and something to find out along the way.
Only experience can tell you if you are on the correct path... :cool:

o_O

Thanks for the info Marcel.

The image you attach was the one I was using in my original post! ;)
 

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