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Ambiguous lighting requirements and useless numbers.

S

simon_the_plant_nerd

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8 Dec 2023
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Location
Scotland
Some of my holiday thoughts today:

Aquatic plants are often sold as “high light” or “medium intensity requirements” or “suitable for low light”. Lighting suggestions for tanks in articles still seem to be made in “watts per gallon” or recommend “high output lights”. Lighting fixtures (LED) are being sold with no real information about light output and vary wildly in cost.

It seems like this is an area of aquatic plant keeping that is very ambiguous.

A cynic may suggest that it’s in the interest of aquarium lighting manufacturers to deliberately keep it vague. The cost of high end LED light fittings in aquatics is eye watering considering the component cost and when compared to similar horticultural fixtures.

None of this matters of course if you are the beneficiary of many years of experience. Or if you are in the financial situation to just keep buying and trying.

But if you’re new to the hobby? You’re maybe a young child deciding what to spend your money on? It’s a bit of a minefield.

Am I right? I’d like to be proven wrong.
 
Isn't that what PAR is for? I realize measuring it is a pain, but I thought low light is 20-ish, medium is 50-ish and high is 100 and higher. I'm not sure where "very high" starts. That applies to the conditions in your tank and not the light itself and like you said, it's not beginner friendly. Bless the people who get a proper par meter and publish the results at different depths/inches off center for a particular light.
 
It is ambiguous. Sure we have PAR as a reference point but we (freshwater planted) don't have a scientific standard to define what is low, medium and high. I remember Hoppy's definition which is rather based on the aquarium communities' trial and error results and his guide is what I go by. Then you have some freshwater aquarium retailers stating 100 PAR is in the low range. Sure it's low in the context of weed growers and some coral tanks but it's ridiculous to think you need 100 PAR to grow things like Anubias well.
 
If you are willing to DIY, Philips sells 50w LED regular screw-in bulbs. If you are able to DIY and hang two of them over your aquarium, you have 100w of LED power for not much money.

I use the Philips 50w bulbs for my (very amateur) photographs/videography, though there are also good reasons why Professionals use expensive studio lighting as well.
 
LED lighting for freshwater aquariums is probably only a few years in and most used t8 or t5 even "shop " lighting with good results previously, trying to work out LED lighting as a comparison can lead to confusion. If possible a fixture with settings for brightness ,most have a ramp up and down if needed l find is easiest ,don't have to break the bank either Nicrew and similar are reasonably priced. For LED retro tubes being able to raise the fixture with adjustable bracket system may help but for me it's all trial and error . @oreo57 may come in on this
 
The light which came with my tank says “269 PAR” on it. How did they measure that? Is that 1mm from the light? is it 100mm from the light? What’s the effect 250mm below the water at the substrate? Is that even “good”? Can I trust that number?

269 PAR is really not much compared to the stuff we have at work (horticultural) but then the ones at work are suspended 4m give or take above the deck and are supplementing ambient light so there’s no comparison.

I’m glad I’m not the only one who thinks it’s all a bit confusing.
 
A par meter is used to measure the light in the aquarium

Aquarium PAR/Quantum Meters | Apogee Instruments

The Apogee MQ-200 is the most popular meter for taking underwater PAR readings for coral reef aquariums. Now offering the MQ-210 and MQ-510, designed for underwater readings.
www.apogeeinstruments.com www.apogeeinstruments.com

They produce a reading that will show how strong the light is in the tank. By moving the meter around the tank and writing down the measurements.

This has been preformed in saltwater aquariums for 25 years now. With fluorescent tubes you can measure how their light diminishes over time by measuring the output every few months.

Any writing on bulbs is useless as each fluorescent tube will age differently.

Many LFS will rent the device to you.
Our club has to par meters and we go to club members homes and map the par of their lighting and help them set up their lights correctly.
 
Well a couple of personal opinions.
Yes the " premium" placed on the top tier aquarium lights is out of proportion to costs of construction.
But then again what isn't.
fishtanksdirect.com

ATI 48 Inch 6x54W SunPower T5HO Aquarium Fixture

ATI ATI3011 Now Available. Buy Your ATI 48 Inch 6x54W SunPower T5HO Aquarium Fixture Direct and Save. Free Shipping on Orders Over $75. Tax-Free.
fishtanksdirect.com fishtanksdirect.com
$603 for a 4 bulb t5HO fixture? Horts are what $100?
Doesn't help that the premium brands really cater to the salt water world that seems to thrive on being overcharged.
Radions, AI Primes, ATI, GHL Mitras ect.
Doesn't help the "lower tiers" to be more cost conscience. Soo charge $100 less than the over-priced upper level.

Manuf doubles the cost to a distributor. distributor doubles the cost to the retailer, retailer doubles the cost to you..
Compound interest..
And that is at best.

As someone who dabbled in building things from scratch with quality parts my current "rule of thumb" is most lights should not exceed $3/watt.
Yea have to fall back to watts which isn't a totally bad nor extinct thing.

Oh brings us back to the increased popularity of buying and using "PAR" meters.
Even that is somewhat controversial with the saltys. Some insist not to chase numbers.
Certainly is a bit controversial in the lower $ fw world.
It would be nice if the manuf ALL gave numbers as to the PPFD output of their lights but lets face it most wouldn't believe them anyways.
And tanks (and testing procedures) are different so it is hard to compare real life vs tests.
Only thing that really needs to go is lumens.
With the increase of RGB fixtures the lumen measurement gets more and more inaccurate as to the actual numbers of photons (which is the most important part)
2000 LUX (lumens/area) is 153.7 "PAR" if you are using only 650nm red leds.
If you use average 6500k white leds that same 2000 LUX is only 26.8 par.

Convert Lux to PPFD - Online Calculator | Waveform Lighting

Online calculator to convert illuminance (lux) to PPFD (micromoles per second per meter squared).
www.waveformlighting.com www.waveformlighting.com
Unfortunately that is the "standard" borrowed from the real world. :)
So if you ranked them
"PAR" in your tank....manuf par in water....manuf par in air (likely)...watts..lumens/lux.


AS to high light vs low light plants..
I "believe" that classification is too simplistic.
Mainly due to the introduction of forced CO2.
Changes the tolerance.
High light par with CO2 is different than high light par without CO2.

In the sunlight world most of the true aquatics are "low light" plants anyways or at the least shade tolerant.
aquaticplantclass.JPG



www.aquaticplantcentral.com

low light plants in high light areas?

www.aquaticplantcentral.com www.aquaticplantcentral.com
With the ease of led dimming best thing is just to buy the light that matches your needs/want and as much dimmable wattage as you can afford (or want to spend)

A long time ago I gave up on the idea of "fairness" in Capitalism.. ;)
 
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Hi all,
oreo57 said:
$603 for a 4 bulb t5HO fixture? Horts are what $100?
Click to expand...
That has always been <"the issue for me">. Horticultural lights have to work, so that is a lot of premium for the magic word <"Aquarium">.
oreo57 said:
AS to high light vs low light plants..
I "believe" that classification is too simplistic.
Mainly due to the introduction of forced CO2.
Changes the tolerance.
Click to expand...
There is a suggestion (by Clive @ceg4048 ?) that "high light" really just means require elevated CO2 levels. This isn't true for plants like <"(Overwintering) Ludwigia sedioides">, they need plenty of everything <"https://www.ccfg.org.uk/wp-content/uploads/2017/11/Conf09_PBurgess.pdf">.
oreo57 said:
In the sunlight world most of the true aquatics are "low light" plants anyways or at the least shade tolerant.
Click to expand...
That was definitely a reason for wanting a floating plant for the <"Duckweed Index">, both access to CO2 and adaptation <"to high light intensity">.

cheers Darrel
 
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Disaronno said:
It is ambiguous. Sure we have PAR as a reference point but we (freshwater planted) don't have a scientific standard to define what is low, medium and high. I remember Hoppy's definition which is rather based on the aquarium communities' trial and error results and his guide is what I go by.
Click to expand...
This isn't unique to our hobby - growing most plants is like this to one extent or another. It's just tough to generalize when there are so many different factors. Best practices are developed over time, but then a breakthrough will challenge the "rules" and everything shifts.
simon_the_plant_nerd said:
269 PAR is really not much compared to the stuff we have at work (horticultural) but then the ones at work are suspended 4m give or take above the deck and are supplementing ambient light so there’s no comparison.
Click to expand...
Horticultural lights also don't have to take color rendition into consideration. Their job is just to grow, our lights have to grow and make the plants look their best.
oreo57 said:
So if you ranked them
"PAR" in your tank....manuf par in water....manuf par in air (likely)...watts..lumens/lux.
Click to expand...
Everybody should write that on the back of their hand.
oreo57 said:
AS to high light vs low light plants..
I "believe" that classification is too simplistic.
Mainly due to the introduction of forced CO2.
Changes the tolerance.
High light par with CO2 is different than high light par without CO2.
Click to expand...
I agree with this, though I think we're still figuring out the threshold of what can be grown without CO2. Come to think of it, I'm not sure how confident we are about the upper threshold with CO2 either, but that's not my area.
 
ElleDee said:
Horticultural lights also don't have to take color rendition into consideration. Their job is just to grow, our lights have to grow and make the plants look their best.
Click to expand...
This is very true. We’re still using a lot of blurple in our greenhouses (formerly metal halides) and growth chambers. A 7000K led fixture is fairly unnecessary for these purposes.

oreo57 said:
$603 for a 4 bulb t5HO fixture? Horts are what $100?
Doesn't help that the premium brands really cater to the salt water world that seems to thrive on being overcharged.
Radions, AI Primes, ATI, GHL Mitras ect.
Doesn't help the "lower tiers" to be more cost conscience. Soo charge $100 less than the over-priced upper level.
Click to expand...

As a former reef keeper, I’m amazed to see how much the prices have jumped up in the last decade. I ran an LED fixture which I chose for colour over much else but in a nano tank, my photosynthetic corals grew well. It was expensive for me back then but a similar light now (same but had Bluetooth for whatever reason?) is over double what I remember paying for mine.

I think I will build my own next light fitting. The electronics is the kind of thing I do day to day. Making it look pretty enough for my wife to accept it in our home… she’s already made so many concessions in that area.
 
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