# LED Lighting for 5 foot Aquarium



## Mike Charlie (18 Jul 2017)

Hi Everyone, first time posting here but been doing aquariums for some time now and have a 108 Gallon tank that I am currently setting up, got some different tetra's, a three spot gourami and a silver dollar (very small at moment). Already decided I want to go with a tetra heaven so I am designing a wet dry filter which can handle more than enough. Now I am looking into what lights I should use, size of tank is 60"Lx18"Dx23"H. I still haven't decided what to keep in the way of plants, but thinking dwarf baby tears for some carpeting.

Anybody got a clue of what LED's lighting I should get?


----------



## alto (19 Jul 2017)

You may want to read this $fish profile - these fish are dedicated plant eaters 

Assuming by dwarf baby tears you mean Hemianthus callitrichoides 'Cuba' & given 23" tank height, expect to pay a decent amount for (high intensity) lighting in order to have reasonable substrate PAR 

Think on the order of Kessil, Giesemann ie exceptional reflectors combined with high intensity lighting


----------



## Mike Charlie (19 Jul 2017)

Yes forgot to mention that part, I currrently have a small light fitted with a t8 tube and some java moss with one part attached to driftwood and rest floating, which silver dollar has been eating away at. I thought I would need a strong one like you suggest I'll have a look and get back with any questions, thank you.


----------



## alto (19 Jul 2017)

Silver dollars get big so even with just one, all your $$ plants will eventually be gone - they can also startle easily which tends to hazardous to plants etc as they mature, definitely sort out a gradual lights on/off if you keep this fish

For algae crew look to snails & fish rather than shrimp re your current fish sound as if they'd easily eat a lot of shrimp rather quickly, even snails may be subject to harassment & loss of body parts so monitor that


----------



## Mike Charlie (19 Jul 2017)

I was looking to move the silver dollar on, I was given two silver dollars when my friends started having problems with his cichlids messing with them, he is more of a temporary guest whilst friend gets another setup.
 Do you think the gourami would bother shrimp? He has never bothered with any other fish even when I had fry in tank, he stayed away from them and kept to his own zone, and that was when he was in a high lz1000 so almost doubled the water size for him.

I've had a look at some kessils and have noticed they do quite a lot of different ones is the h80 good? Also noticed it says coverage is up to 24" surface coverage would that mean I would get a wider spread at bottom by enough to only need two instead of three as £450 on lights will eat into the rest of my budget (so will £300 mind but they do seem good quality and hopefully the plants will love them)


----------



## Zeus. (19 Jul 2017)

Mike Charlie said:


> size of tank is 60"Lx18"Dx23"H. I still haven't decided what to keep in the way of plants, but thinking dwarf baby tears for some carpeting.



Same depth as mine, I have four Kessil 160 tuna suns and six 24w T5, growing my carpet of mini grass and Micro swords has been tricky, as to get enough light at substrate level makes a lot of light in the upper areas of the tank which render aglea an issue. My carpet plants are easy/medium but your thinking of HC thats *hard* you will need more light than me. I use two inline CO2 atomisers and have used two 6Kg bottles so far this year third is nearly empty too, for HC you will need a excellent [CO2] at the substrate level too. All doable OFC but not for the faint hearted or shallow pockets either IMO


----------



## alto (19 Jul 2017)

I have an A80 but haven't got the tank yet - rumour is the improved reflector design has this light putting out similar intensity/PAR to the A160, no word if/when Kessil will have new model A160 & A360 out with the new reflector design 
(expect a reduction in older model pricing if this happens BUT Kessil may hold off until most stock is out of their warehouse)

Only the A360 really does a 24" surface area with decent PAR over the entire area
The A160 does an 18" surface area
The A80 has also been quoted for that 18" surface area

You'll find more A80 discussion on Reef sites than freshwater planted 

It's quite possible to gradually add lights & plants to the tank to keep budget in check, have the substrate in wherever you want HC eventually, but only plant the zones where you have the light intensity from 2 Kessils (example), then as budget allows, add another light etc - at this stage you should be able to propagate your existing HC etc into the new planting zone so only lamp cost would need to be budgeted 


M 'Monte Carlo' is much more tolerant of light & CO2 variations than HC - if you really want HC I suggest you do a practise run in a nano tank first, it's also much more labour intensive

If you really want HC in this tank, I'd begin with either a dry start & then gradually flood ie don't add water to 23" tank height but only 12", allow it to establish (2-6 weeks depending), then increase water column to 16-18", wait for response (another 3-4 weeks at least) & so on ... 
You want to wait at each water height change for HC to adapt to new PAR & CO2 etc, wait through at least 2 trim cycles to be certain the growth you're seeing reflects the new conditions 

I mentioned either dry start or ???
- rather than an actual dry start, begin with a water depth of 4" or so, this is enough to require submerse growth but also ensure good light & CO2 


Of course this means fish elsewhere during thIs time, but it will allow shrimp colonies to establish - & they'll keep any melting HC in check (ie eaten, so make sure you begin with sufficient shrimp for your HC area)

Gouramis can definitely go anyway wrt shrimp: total ignore, opportunity snatchers, dedicated hunters
This applies to most fish that naturally hunt crustaceans etc in their wild habitat, eg, Betta, Rams, even tetras ... rasboras seem to ignore shrimp activity more than most tetras will (some tetras while not actively hunting shrimp will pay so much attention to shrimp activity that shrimp will mostly remain hidden & subsequently pretty useless as algae crew)


----------



## Mike Charlie (20 Jul 2017)

Wow Zeus that's a lot more lighting than I would of thought, that's around reef level isn't it? 

Yeah I like the look of Monte Carlo as well alto, if that's easier might look at that, obviously haven't budgeted for lights properly at all was thinking more £150-£250 at first, now looks like I will need to spend close to £1000 if not more, hopefully nothing else is more than I thought or I will have a very unhappy wife. Might look more at some metal halides see if I can find any good ones


----------



## alto (20 Jul 2017)

MH is passé - so you should be able to get some good deals on MH systems BUT they are $$ to run as bulb must be replaced every 6-12months (spectrum & energy degrade much more than with T5's etc, LED are much more stable & cheapest to run long term) & in some areas you'll be limited by bulb availability (make sure you've a good online source with cheap shipping etc - I can't get cheap shipping so I always suggest this be part of the budget)

If tank was a more standard height 14-16in, lighting can be done cheaply & well within your initial budget - you can always run the tank with a 14in water column (measure from substrate surface) & add in a mister for an interesting upper tank half BUT if you include many submerse plants, they will quickly block light to substrate plants 
A "wall" effect of submerse plants kept trimmed bonsai style could work well (though this setup needs to be added into the budget as well then)

I like deep (tall) tanks as I think most fish prefer less shallow water columns (look at natural habitats & even those considered "shallow" are at least 18" deep).

Note that many of the T5 systems on the market are very poorly designed - reflector material & shape is poor, bulbs placed much too close etc 

4 HOT5 properly spaced across your 18" tank width & good reflectors can supply sufficient light to grow most plants, including MC (HC would take some special consideration  )
BUT the 60" length is an "odd" so look at costs of running those T5's - you want HO & proper spectrum on these bulbs due to the water column height, I had considered a 60in tank some years ago but couldn't source bulbs locally (& the light unit was going to cost double what I could get on a 72" unit)

3 Kessil A360 would provide a nice clean look, check the classified section here, there were a couple for sale but make sure of warrany transfer etc & consider if you're really getting a deal should a light fail 
The tank would also look very good with just 2 A360 to start, adding the third next year etc - or you might get a bit of a discount by purchasing all 3 ... you could do a light at each end & a shaded area in the middle etc
This would also reduce plant start up costs


----------



## alto (20 Jul 2017)

You might see if these are still available


----------



## Zeus. (20 Jul 2017)

Mike Charlie said:


> Wow Zeus that's a lot more lighting than I would of thought,



Light has 50cm of water to penetrateplus glass covers, Kessils website advised six to eight , I dont have the kessils high either. Kessils only have a year warrenty also . Kessil controller £100 too. I use  a siemens Programmable Logic Controller 'PLC' to control the lights intensity/ spectrum ,PLC not cheap but does run every thing form lights, CO2, auto dosing, water temp, air pump, plus has holiday mode settings at press of a button.

My tank is 150x60x60cm


----------



## alto (20 Jul 2017)

You can see the light effect of 2 Kessil A360 on George Farmer's EA1200 scape 

Check his YouTube channel for an EA1800 scape with (again) 2 Kessil A360

For that tank height the A360 has significantly better substrate PAR, so if you want HC, definitely consider the A360's
For MC you have more options, including the A160's


----------



## Mike Charlie (20 Jul 2017)

Didn't even think about actually getting the bulbs for MH will speak to some of my locals and see what they say, one can normally order anything I want in equipment wise. On the 4 HOT5 that's 4 bulbs and not 4 fixtures right? I found a couple that could be ok so just need to locate bulbs to work out price of that as well. I saw on FB somebody was selling 3 kessils a360 for £150 they were the older models apparently but still sounded good, unfortunately they had gone before I found them . Also unfortunate is fact that I don't have access to the classified area yet but as soon as I post enough I will check that out. I was thinking of doing a lava rock cave system on one end which wouldn't need lighting so 2 a360s would probably do quite well in that case.


----------



## Mike Charlie (20 Jul 2017)

I guess with the glass covers and the 50 cm water it would be a lot of light needed. Using a PLC seems quite advanced but I checked out the thread when I joined, could you do the same with something like an arduino and some extension boards? If so then that's some money back to the tank for better equipment


----------



## Mike Charlie (21 Jul 2017)

Checked out the tank, alto, the kessils do give a very nice well lit tank, and it looks almost natural (to me it does anyway), might have to find some money to buy the 360s now, wonder how wife would react if she knew how much I'm spending (she thinks full thing included tank and stand is £500)


----------



## alto (21 Jul 2017)

Older model Kessils are A350w/A150w indicating a "wide" 120degree lens (60 - 90 degree was "standard" at the time) 

- these will no longer have any warranty & run 20-30% lower energy than the A360/A160 series, they were selling as low as half price "new"  when the 60 series was released 

- you could check direct with Kessil & inquire if any still exist in their stock


----------



## Zeus. (21 Jul 2017)

Mike Charlie said:


> could you do the same with something like an arduino and some extension boards?



Not sure about that Ian-m would be the best member to ask IMO. PLC isnt hard to do its more the cost, once setup its a dream, no issue if power cut etc, adjust times form PC over Lan, check stuff on mobile. Thinking of doing another PLC for another tank I picked up.


----------



## ian_m (21 Jul 2017)

https://www.iquaticsonline.co.uk/un...-universal-4-tube-150cm.html?___store=default

I use this lighting. Very bright using both iquatics supplied tubes and Juwel hi-lite day tubes.


----------



## Mike Charlie (21 Jul 2017)

I will have to look into it more might try, reason I ask is I have a spare arduino and bunch of electronic bits. If not will probably get a PLC one day anyway.

Sorry alto they didn't actually name model I was reading it off the side of blurred picture so was probably the a350w then. I'll get in contact with them and see if I can get a deal.

Ian these seem exactly like what I think of when I thought of lighting, do you think they would be ok for carpeting the Monte Carlo? It seems to follow just above the 2 watts per gallon rule, maybe if I add a reflector, but it doesn't seem to want me to on the site (on phone at least will have to check on computer when I get chance) it would be ok, if not maybe this could be a starting light with kessils as well, something for me to think about.


----------



## Mike Charlie (21 Jul 2017)

Right so metal halides are out as no local providers still got to speak to kessil though


----------



## ian_m (21 Jul 2017)

Mike Charlie said:


> do you think they would be ok for carpeting the Monte Carlo?


Yes. I Grow HC no problem with light output, just fish tend to lift it up and eat the roots away 

The supplied tubes are too red/pink for my linking (probably 6500K), still makes plants grow fine. But I use in combination with two Juwel Hi-Lite day tubes (8000K), make the plants looks a lot "greener".

I have reflectors as well.


----------



## Zeus. (21 Jul 2017)

ian_m said:


> HC no problem with light output



How deep is your tank Ian?


----------



## ian_m (21 Jul 2017)

Zeus. said:


> How deep is your tank Ian?


Only about 45 cm. The reflectors make a lot of difference, focusing the light downwards.


----------



## Mike Charlie (21 Jul 2017)

Is that 45cm water column if you measure from top of substrate or just tank height, if it's substrate then might just go that route as I will be building my substrate thickish, although one of local shops has some leds that they are getting me information on so will wait to see that as well.


----------



## ian_m (21 Jul 2017)

Mike Charlie said:


> Is that 45cm water column if you measure from top of substrate or just tank height


Height from tubes to substrate surface.


----------



## Mike Charlie (21 Jul 2017)

Right so that should be plenty for what I want then, going to check out some of there other products a bit more as I've seen a 6 bulb one so could play with something like a couple of lights extra at different times of day in different colours to give better look, still might not look natural but cheaper I can make this the better


----------



## Zeus. (21 Jul 2017)

mine is 50cm from water surface to substrate level, Have ribbed tank and 24w T5 tubes with refectors, T5s resting on glass and kessils 15cm above glass


----------



## Mike Charlie (21 Jul 2017)

Found these as well now https://www.fish-fish-fish.com/aqua...bquWDrZp0ytsbNkKpWHZG8eDyaZ-i2bRoCDNMQAvD_BwE they state that they replace 54 watt t5 for same light quality, does this have any ring of truth do you think? I have led spotlights in house and know they are a lot brighter than there wattage suggests. If that's the case then 4 of these would provide same light intensity as the one Ian linked for a cheaper running cost which would allow me more monthly treats for the tank.


----------



## Mike Charlie (21 Jul 2017)

Oh also they are 8000 kelvin like the tubes Ian uses


----------



## ian_m (21 Jul 2017)

Mike Charlie said:


> Found these as well now https://www.fish-fish-fish.com/aqua...bquWDrZp0ytsbNkKpWHZG8eDyaZ-i2bRoCDNMQAvD_BwE they state that they replace 54 watt t5 for same light quality


I would steer clear. Probably OK, but they don't state any lumen figures so you can't compare and seem a tad cheap for their supposed T5 length.

An Arcadia 54W T5 HO tube is about 5000 lumens.

These are proper LED T5 replacements. The equivalent 54W T5 length of these is 5400 lumens. (but notice that consumes 62W, so LED's are not always lower power than fluorescent). A proper job.
https://www.allpondsolutions.co.uk/aquarium/lighting/aquatlantis-led/universal-lighting-freshwater/


----------



## alto (21 Jul 2017)

Just enquire as to which LED are used - for water column depth above 45cm, you need minimum 1watt LED in order to have significant PAR at substrate level

I tried Current USA Satellite LED + PRO (1.2 watt SMD LED) on my 60cm x 45cm x 53cm (high) tank - light at substrate was like shade, maybe Anubias would manage ... on my 36cm high tank it's brilliant at substrate level

as an example 
100 PAR at 45cm water depth
5 - 10 - 20 PAR at 55cm water depth 
This is a memory estimate rather than actual values, takes a good deal of searching to find PAR values through water (through air is useless) for the various LEDs that are used in lighting 
Then reflectors & lens & cool running come in as factors 

Manufacturers also tend to report the highest PAR measured rather than showing the range that actually occurs across the suggested "suitable use" surface area (ie that 24" surface area) - I believe Ecotech may have some decent 3D PAR graphs in their technical pages 

Sanjay Joshi has many in his articles, going back to MH & T5 & now LED (though some manufactures requested their models be removed from his articles)


----------



## Zeus. (21 Jul 2017)

I got Philips TL5 HO 90 De Luxe 24W 965 (MASTER) | 55cm - Daylight which is very close to the colour of the kessil 160 when on full spectrum, as they had no 24w tropical in when I got my ballast.

yours size would be ( I think) 
Philips TL5 HO 90 De Luxe 54W 965 (MASTER) | 115cm - Daylight £4.98 each, Light Output (Lumen) 4300


----------



## Mike Charlie (21 Jul 2017)

Yeah didn't think about checking the lumens after checking a few German sites (English sites don't seem to include it?) it stated as being just under 2000 definitely give it a miss in that case, I'm confused about the leds using more electricity for same rating, if the led is more than the t5 in cost and running cost what would be the benefit of using leds instead?


----------



## alto (21 Jul 2017)

You might contact Euroaquatics for PAR values etc


----------



## Mike Charlie (21 Jul 2017)

Zeus you state t5 has light output of 4300, would reflectors make that equivalent to 8600? I'm confused how undirected light strength is calculated also so much cheaper than buying from the fish shop sometimes forget how much something increases because it's for aquarium use.


----------



## ian_m (22 Jul 2017)

Mike Charlie said:


> Zeus you state t5 has light output of 4300, would reflectors make that equivalent to 8600?


No the output of a T5 tube lumens is in all directions, adding a reflector focusses the light into the tank, rather than into room and/or aquarium hood and/or your eyes when tank fiddling.

See here for pictures.
https://www.iquaticsonline.co.uk/reflectors/t5-reflectors/2-x-54w-t5-aluminium-reflector.html



Mike Charlie said:


> I'm confused about the leds using more electricity for same rating, if the led is more than the t5 in cost and running cost what would be the benefit of using leds instead?


Yes people get on their high horses about LED's using less power, greenness etc but that is not always 100% true.

I good T5 HO tube will do about 100 Lumens per Watt power. eg the 54W Arcadia tube.

Smaller lower power LED's (say 1/3 W each) as used by cheaper LED light suppliers are around 30-40 lumens per Watt, this is still significantly greater than a standard incandescent light bulb of 5 lumens per Watt (15 Lumens per Watt for halogen bulbs). The Aqualantis units are 90 lumens per Watt so not too different from T5 HO. To get greater efficiency you need to move to 1W, 3W & 10W single LED's where efficiencies start at over 100 Lumens per Watt. But these LED's start at a couple of £ each thus the light fixture will not be cheap, which is why proper aquatic LED lights cost in the £100's.

Main advantage of LED's is possibly, though always as you have seen, lower running cost. However 2 x 54W T5 HO cost about £50 a year to run @ 8 hours a day, LED's might be 3/4 that so saving £15 a year. You need to work out pay back time.

Another LED advantage is life time. LED's if designed properly ie LED's cooled correctly & properly (non Chinese !!!) electronics will last 50,000 hours to 80% brightness (17 years at 8 hours a day). T5 HO are rated 80% brightness in 20,000 hours. However in practice cheaper LED's electronics will fail before the LED's and T5 tubes heaters (at the ends of the tubes) will fail before the light output drops.


----------



## Mike Charlie (22 Jul 2017)

Right so it was more to direct.

If they last longer than it might still be worth looking at other ones, I'm confused about lumens on LEDs, what would penetrate the water more or would it be equal, 1 100w producing 10000 lumens or 10 10w producing 1000 lumens each

I was starting to think about building my own LEDs I know how to do soldering and the electronic side but the lighting part really confuses me getting the output correct


----------



## Zeus. (22 Jul 2017)

To throw another spanner in the works lumens is only a rough guide. PAR readings are the gold standard as it's measure of the light the plants can use. PAR at various depths of water better still, as some light penitration is better than others.

Sent from Mountolympus via neural interface


----------



## Mike Charlie (22 Jul 2017)

Oh come on I get hang of one aspect of the lights and then there something else haha  
Is lumen more or less directly related to PAR as in 10,000 lumens would give better PAR then 5000 lumens all the time or would some 5000 lumen lights be better than some 10,000 lumens


----------



## ian_m (22 Jul 2017)

Mike Charlie said:


> Is lumen more or less directly related to PAR as in 10,000 lumens would give better PAR then 5000 lumens all the time or would some 5000 lumen lights be better than some 10,000 lumens


Yip spanner in works. PAR (photosynthetic available radiation) is the bit of light spectrum that plants can use. PAR from T5 is generally higher than the same lumen LED, just because T5 have a broader output spectrum. But by mixing different colour LED's, rather than just having white one can get higher PAR values. Again more expensive LED fixtures contain a mix of LED's, white, red, green and blue to have both high PAR values and high lumens and a light output that makes plants stand out eg Look at Kessils, high lumens and high PAR (and high price).


----------



## Mike Charlie (22 Jul 2017)

I've tried looking earlier for lumen output of kessils I can get what people are measuring PAR at but not lumens might email directly and ask


----------



## alto (22 Jul 2017)

And then there is PUR 

Which is really the most applicable measurement 

This is a decent summary article 

Fortunately you can just add "light" & plants will grow
- getting technical is helpful when designing a system & matching plant goals to light sources

If you run 45cm or less water column height, it's a lot simpler (& cheaper)

The only time I even glance at lumens is when it's the only information available, & then it's just the starting point, decent/suitable lumens means it's worthing pursueing PAR/PUR data


----------



## Mike Charlie (22 Jul 2017)

I honestly thought you was having me on for a second then , I gave it a check and i have actually come across it briefly before just not named PUR, I'll give me of a look now and we will see how confused I get getting head through this part before one of you tells me there is another factor to consider that an acronym to confuse me more haha

Interestingly I decided against doing a reef tank because I thought a nice planted tank would be easier overall and a bit cheaper, price gap is closing and still seems very involved, but I still can't wait to create the idea I have in my head and isn't that what it's all about, slightly unrelated note but is pea gravel ok to use to lift height of substrate thinking higher back than front and looking into best way to do that.


----------



## alto (22 Jul 2017)

Lava rock is better as lighter & more porous, stick in nylon stocking bags with shift room so you can adjust the shape - I'll look for the awesome journal for this 

Is the tank ordered or already present? Just switch to 45cm height & you're golden


----------



## alto (22 Jul 2017)

Pedro Rosa

Dark Land


----------



## Mike Charlie (22 Jul 2017)

I'll have to get some more lava rock the how fine should it be, near to powder or more like crushed?

Tanks is already here, actually got it for free just had to pay for delivery, very good shape apart from slight chips in top of glass, just cosmetically though and will be wrapping top once got the lights together so it will look like new as before that it was just used to mix water so no scratches at all.


----------



## alto (22 Jul 2017)

Crushed to briquet size pieces are good, depends how much height you want to add


----------



## alto (22 Jul 2017)

Photos 
Compare to ADA power sand


----------



## Mike Charlie (22 Jul 2017)

I'll order some more then, is the aggregate one the same as the one you get in fish shops, LFS says it is but it may require more rinsing which is understandable, however I know in this hobby just because they have same name it doesn't mean it's the same


----------



## Mike Charlie (24 Jul 2017)

Just got the aggregate type ordered anyway if not can redo garden.

So after reading a lot of articles on pur par and lumens I believe that I understand, is it as follows; if lumens is high in the correct PUR then PAR for the plants will be high? Have I understood correctly or is there still something I missed?


----------



## alto (24 Jul 2017)

Pretty much  - but you'll have difficulty getting PUR values out of retailers/manufacturers, especially for any lamps that are manufactured under licence in other countries (lights will be built to some "specification" but actual components used tend to vary between lots)
A company that manufactures & retails is more likely to have reliable data, but some of these companies won't report PAR as measurements can be subjective (especially wrt sensory array used - take a read on the method & equipment used by Sanjay Joshi  - few hobbiests have anything like, or the technical skills)

You didn't supply a link to the aggregate you ordered so no idea on that


----------



## Mike Charlie (24 Jul 2017)

I meant just in general the ones that get supplied is same as in aquarium safe and there isn't any extra prep other than more rinsing, it's from a local supplier so no link but it looks the same visually just smaller.

I'll have a look at the equipment they use hopefully I will understand some of it. In regards to getting the correct PUR for high PAR there was a graph included so could we not choose wavelengths that match the graph to eachoeve the high PAR ratings?


----------



## Mike Charlie (24 Jul 2017)

Also something that I wondered let's say I like the tank to be a certain white but it's not beneficial in PUR could I use that couloir along with beneficial colours to obtain high PAR or would the wrong colour actually lower the PAR rating assuming the colour I want was in addition to the rest and not replacing one of the beneficial colour


----------



## Mike Charlie (24 Jul 2017)

Also whilst I was looking up leds I made note of one that could do 4500 lux from 5 watts now I know it was in the wrong spectrum it is useless but do them numbers sound right before that I was not finding much over 200 lux per watt never mind 900 lux per watt that this suggests, I will try to find LED that stated this but does this sound right?


----------



## micheljq (25 Jul 2017)

Lux must be rated with the distance to the light souce at which the mesure was taken, lux by itself means nothing.

Michel.


----------



## ian_m (25 Jul 2017)

Lux has nothing to do with distance. One lux is one lumen of light spread over one square meter. Thus if I project my 5000 lumen T5 light onto one square meter this is 5000 lux.


----------



## Mike Charlie (24 Aug 2017)

Just thought I would let everyone know I went the T5HO method and looking at it over the tank I am glad I choose it, it definitely was easier to find and then just choose some bulbs in right spectrum so much easier than LED's, thanks for the help


----------



## micheljq (24 Aug 2017)

ian_m said:


> Lux has nothing to do with distance. One lux is one lumen of light spread over one square meter. Thus if I project my 5000 lumen T5 light onto one square meter this is 5000 lux.



At what distance?  That does not sound right, take a luxmeter and you will see that the lux measure will go down a lot the more far away you are from the light source.

Michel.


----------

