Stable CO2

Zeus.

Member
Joined
1 Oct 2016
Messages
3,371
Location
Yorkshire,UK
Zozo not to be contradictory I’m just raising some questions.

I think we are all on the same page i.e.we are having a discussion aka peer review, no body is saying these are the facts and we are all open minded on the subject ;)

The statement that no other lamp could provide what the sun provides in terms of light intensity is I’m afraid not in line with reality.

Think @Andrew T has made a very valid point here esp we consider Reflection and Refraction with our tanks with fixed lights the incident angle is constant so the light intensity will be constant if the lights output remains constant. However with natural light the incident angle of the light will be constantly changing as well as the light intensity, also the incident angle will change on a daily basis as the sun climbs/falls in the sky. So maybe our fixed lights above our tanks do bombard our plants with more photons than a tank receiving natural daylight light in a single photoperiod, not says always do, but maybe more than with think :angelic:
 

zozo

Member
Joined
16 Apr 2015
Messages
7,473
Location
Netherlands
I found a report from a meteorology institute with sunlight Lux measurements somewhere in the average middle of my country, which is approximately for the biggest part situated 5 metres below sea level. This would mean the same measurement done at places above sea level would give higher numbers. Since at the top of one of world's highest accessible mountains it's measured 5 x higher.

The report doesn't say day time and date but we can assume it's an average throughout clear sky days.

Results are:
Direct sunlight: 130 000 lux
Indirect - Daylight: 20 000 lux

Compared to a Phillips HPI-T Grow light 1000 watts Metal Halide = 85000 lumen

Lux = Lumen/m², Correct? Meaning in case of artificial light according to the height of the lamp placed above the surface it should illuminate means less lumen/m².

Actually no idea how it relates exactly and how Phillips measured it, i guess to put it in a reflector and make it illuminate 1m² exact and take some Lux measurements. At whatever. a height that maybe. Anyway a pretty darn beast of a lamp not yet coming close.

Another experience i did that made me wonder. I once had a lily flowering in of my at the time High Tech aquarium in the month November. It was illuminated with about 10.000 lumens LED fixture x 50cm above the tank. And daylight flowering lilies, close their flowers when its getting dark.
DSCF5300.jpg

The fun part that baffled me was... The tank stood 1 metre next to a North-East facing window receiving a tad indirect daylight. The lights were on till 9 pm, but the sunset was at around 6pm. And despite the LED lights still operating at 100% at 6pm the Lily flower closed 3 hours to early. It didn't react to the artificial light but rather to the indirect daylight from outside.

Made me scratch behind me ears and wonder what is in the light? Why does my Lily flower prefer the low natural daylight during wintertime above my 10.000 lumen LED fixture?

I don't know, it just did.

Was it the intensity or is artificial light missing some parts of the spectrum the plant reacts to? It beats me and knocks me off my shoes..
Another what you see is what you get mystery. :)
 

Zeus.

Member
Joined
1 Oct 2016
Messages
3,371
Location
Yorkshire,UK
[QUOTE="zozo, post: 592866, member: 13448"
]Direct sunlight: 130 000 lux
Compared to a Phillips HPI-T Grow light 1000 watts Metal Halide = 85000 lumen[/QUOTE]

So sunlight is double the Metal Halide but relatively the same order of magnitude

Light penetration into fresh water

upload_2020-4-5_11-58-43.png


So therefore the light absorption coefficients will be higher in our tanks with artificial light compare to natural sunlight due to the incident angle of the light source.

So I would wouldn't be surprised if the Grow light 1000 watts Metal Halide yield more lux/PAR then natural sunlight at any given depth in our tanks and the incident angle of the metal halide is constant, but the sunlight is variable though out the day so the net light will also be greater with the metal halide also.
 

dw1305

Expert
Joined
7 Apr 2008
Messages
10,958
Location
nr Bath
Hi all,
I'm pretty sure that light intensity at midday in the tropics is going to be an order of magnitude larger than anything that we can produce with a lamp. I'll try and find a reference that quotes the different measures of light intensity. For sunlight you should be able to equate light intensity with PAR.

cheers Darrel
 

jaypeecee

Member
Joined
21 Jan 2015
Messages
1,460
Location
Bracknell

zozo

Member
Joined
16 Apr 2015
Messages
7,473
Location
Netherlands
So I would wouldn't be surprised if the Grow light 1000 watts Metal Halide yield more lux/PAR then natural sunlight at any given depth in our tanks and the incident angle of the metal halide is constant, but the sunlight is variable though out the day so the net light will also be greater with the metal halide also.

I envy you that you understand all this matter... But who in their right mind (No pun intended) illuminates an average indoor aquarium with an 85.000 lumen 1000 watt Metal Halide? Would be quite a task to daily top off evaporation.
 
Last edited:

Tim Harrison

Super Moderator
Staff member
Joined
5 Nov 2011
Messages
7,965
Location
UK
Regarding incident angle of the sun, remember it's also an aquarium with glass sides so that doesn't necessarily apply in exactly the same way as it would to a lake or pond etc; it could potentially get a lot more sun.

It's an old Zinc bathtub and a sort of aquaponic filter and a little aquarium hooked together. Approximately 350 litres, it's a closed system that needs an occasional water change if i like to add fresh water
That constant flow of water filtered through high plant biomass could also be an additional reason the aquarium is algae free, especially when you consider the aquarium is only a relatively small window on what must be an incredibly stable system :)
 

zozo

Member
Joined
16 Apr 2015
Messages
7,473
Location
Netherlands
Regarding incident angle of the sun, remember it's also an aquarium with glass sides so that doesn't necessarily apply in exactly the same way as it would to a lake or pond etc; it could potentially get a lot more sun.


That constant flow of water filtered through high plant biomass could also be an additional reason the aquarium is algae free, especially when you consider the aquarium is only a relatively small window on what must be an incredibly stable system :)

That's also my best guess.. :) Plant mass is king! And before it has this i always see algae growth, but it vanishes as soon as the plants kick in as soon as sun intensity goes bonkers.

 

Zeus.

Member
Joined
1 Oct 2016
Messages
3,371
Location
Yorkshire,UK
illuminates an average indoor aquarium with an 85.000 lumen 1000 watt Metal Halide?

well the running cost would be quite a bit alone. But yes I must confesses I had overlooked the amount of light the Hetal halide was outputting:oops: :thumbup:

Checked out the ADA RGB solar for comparison

upload_2020-4-5_18-38-12.png


which has an output of 3000-3500lm which converts to 21,000 Lux output at 30cm above the water (Lux (lx) measures illuminance, which is the amount of light on a surface per unit area.) at 30cm above the water

So for the Phillips HPI-T Grow light 1000 watts Metal Halide the output in lux would be height and reflexor dependant as well, with the right reflector and 30cm from water it would make the direct sunlight seem dim.

But yes direct Sunlight has x5+ the output in Lux than an ADA RGB Solar, but ADA solar directly above tank so incidence angle better so more light will penetrate, we would need to calculate the Solar Zenith Angle. At the equator its 90 degrees and for Me and Zozo its about the same all year round maxing at about 60 62 degrees Here

So without doing the maths OFC with an incidence angle of 60 degrees for the Sun and 90 degrees for the ADA RGB solar it would be a close race on a mid summers day, but for a six hour period think the ADA light would yield a higher net value
 

Tim Harrison

Super Moderator
Staff member
Joined
5 Nov 2011
Messages
7,965
Location
UK
That's also my best guess.. :) Plant mass is king! And before it has this i always see algae growth, but it vanishes as soon as the plants kick in as soon as sun intensity goes bonkers.

Those mutton chops can't be real, they must be self-adhesive or attached using Velcro on or something o_O
 

jaypeecee

Member
Joined
21 Jan 2015
Messages
1,460
Location
Bracknell
Hi Folks,

I see no mention of PAR in the ADA Solar RGB spec. Par for the course (pun intended). No spectrum either - therefore difficult to compare with sunlight.

JPC
 
Last edited:

Zeus.

Member
Joined
1 Oct 2016
Messages
3,371
Location
Yorkshire,UK
Hi Folks,

I see no mention of PAR in the ADA Solar RGB spec. Par for the course (pun intended). No spectrum either - so difficult to compare with sunlight.

JPC

IDD :rolleyes: Typical manufacturers using units of measurement that we are not really interested in Lux and lumen when all we are interested in is PAR, but you have to use what you can to compare.
 

Bryce

Member
Joined
27 Feb 2020
Messages
51
Location
Phoenix Az
Well this subject has been a good one . The OP original question sort of got lost . [Hi what’s the best way to know you have stable CO2? ] The answer is do you have good plant growth? You can measure, test etc.. but it’s simpler than that.. do you have minimal algea? Are your plants growing? I’m not a scientist ,biologist or plant expert by any means. I’m just a guy who enjoys growing plants in a tank full of water no more no less. I can’t answer all the science questions but, a little common sense will go a long way.
 

dw1305

Expert
Joined
7 Apr 2008
Messages
10,958
Location
nr Bath
Hi all,
Well this subject has been a good one . The OP original question sort of got lost . [Hi what’s the best way to know you have stable CO2? ] The answer is do you have good plant growth? You can measure, test etc.. but it’s simpler than that.. do you have minimal algea? Are your plants growing? I’m not a scientist ,biologist or plant expert by any means. I’m just a guy who enjoys growing plants in a tank full of water no more no less. I can’t answer all the science questions but, a little common sense will go a long way.
I think you have to differentiate between low tech and hi tech.

In a low tech, the plant mass is going to effectively deplete the CO2 during the photoperiod, you can get a measure of this by the variation in pH (as the CO2:O2 ratio changes). A larger plant mass will deplete that CO2 more effectively, it's back to <"Canford Park again">. During photosynthesis one molecule of O2 is produced for every molecule of CO2 incorporated. Because plants are carbon based, and they grow, we can see that they are net CO2 consumers and net oxygen producers.

There are ways of "flattening the curve" of CO2 depletion, the one I would recommend would be increasing <"the gas exchange surface area">. There is a much fuller discussion of this in <"maxing CO2 in Low Techs">, where this graph comes from.

5cxa-jpg.jpg

Partially why I like a floating plant in the tanks is that they aren't ever CO2 limited, they have <"Diana Walstad's "aerial advantage">. This is also why I think that the <"no water changes, low tech because they cause CO2 fluctuation"> isn't an argument that holds any water.

High Tech.
I'm not a CO2 user, but I think the idea behind the "stable 30ppm of CO2" during the photoperiod was so that plants aren't carbon limited, and can effectively make use of the PAR and nutrients available to them. You can still end up in a situation where CO2 is depleted (because PAR drives photosynthesis), but you can't safely go much beyond 30 ppm CO2 without asphyxiating your fish. If you don't have any livestock you could definitely add more CO2 and the plants could then utilise more PAR and nutrients.

cheers Darrel
 
Last edited:

Similar threads

Top