# Cree lights / lumens / eBay / planted tanks.



## fleabilly (11 Oct 2012)

So I was thinking about getting these...

http://www.ebay.co.uk/itm/10-PCX-CREE-G ... 08400?var=

 I have a heavily planted tank.
80x40x30
24.7 gallons.

In order to reach the desired LSI of 30
I need roughly 11,160.45 of lumen power.
With 10 of these Cree gu10's I will have roughly 9000
Or a LSI of 24.

Does that sound right?
Or should I push for more?

Cheers







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## wazuck (11 Oct 2012)

That is a lot of light. Note the beam angle. This tell us that each led has optics which are used to place more of the light in one spot (much like reflectors on tubes). These lights also punch through the water a lot like metal halides. Leds also put out more usable light per watt than normal bulbs. So loosely going by WPG your looking at more like 4+ WPG. I wouldn't put more light over the tank. If you feel like you need all 10bulbs for light spread I suggest raising them high above the tank. Hope this helps.


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## Radik (11 Oct 2012)

Sounds like lot of light for this size of tank. Take 60Beam angled. 

Because they are with lens such concentrated beam from CREE LED is 2-3x more powerful than standard T5. So around 10 of these =120W of led power which might equate to around 300W of T5 power or l2x150W metal halide very easy. That's enormous light.

Try it with 5 first and jut spread them over tank and around 30cm+ above.

Also LSI or whatever is useless value for planted aquarium, we use PAR and PUR for our purpose. Cheapest PAR meter you can get is Seneye reef and it is pretty accurate. Aim for 70PAR which will grow you pretty everything and is considered low/medium light. Then you just adjusts height for more or less light.


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## SlavIP (14 Oct 2012)

Radik said:
			
		

> Sounds like lot of light for this size of tank. Take 60Beam angled.
> 
> Because they are with lens such concentrated beam from CREE LED is 2-3x more powerful than standard T5. So around 10 of these =120W of led power which might equate to around 300W of T5 power or l2x150W metal halide very easy. That's enormous light.
> 
> ...



Hi!Can you give me any info or link of this light?Where I can get it for my 70 gallons tank.I have echinodoruses ,rottalas and ludwigia.thanks!


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## mvasingh (14 Oct 2012)

Hi
Can you tell us how you plan to build your setup?

MIKE


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## Palm Tree (14 Oct 2012)

Also it may be worth noteing that those bulbs are quite expensive, have a look around on ebay for cheaper 12w led gu10's or even go for 10x 6w or 9w bulbs for a more even spread of light and to avoid spotlighting. You can also get dimmable led bulbs so that might be something to look into.


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## fleabilly (14 Oct 2012)

Every day 
I read something new that sets me off in a different direction.
Bottom line I guess is saving money.
Long and short term.
Just frustrating to try to grasp the optimal light given led

Most led cater to marine tanks.
So it is hard to find anything in relationship to tropical.
I have looked into led grow lights. (Cannabis)
I have researched the red and blue spectrums, and how they effect plant growth.
From what I understand blue is better for plant growth...(bushy ness)
Red is more for flowering.
So if this be the case how much blue would you need for say 25 gallons?
(With a little dimmable white light for a more pleasurable view.)
Depth apparently is not so relative because blue light travels the deepest.
There is a large amount of information about lumens, par, pur... Out there.
And it all seems to be attached to someone's light, that beats all the rest.

I would like a standard laymen equation for led that is as simple as the old watt to gallon. 
For instants...
If I used a blue led of a specific wattage and angle.
And compared it to a led of cool white (6500k) same wattage and angle.
How would both of these compare to a T5
In say pur.
Which from what I can tell is the best litmus test of economical lighting.

Last article I read had me thinking that my best option is the TMC grolight 500.
But after reading the whole article, I became remotely suspicious that the whole blogspot was a selling arena for the lights. And they were just telling me what I want to hear. That two grolights 500 will be more than enough for my 25g. 

So next pay check I will purchase these,
Unless someone out there can convince me otherwise.

Cheers for all your info.
In has been useful.

R

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## ceg4048 (15 Oct 2012)

Hello,
        You are completely off in the deep end of the pool. The only thing you need to worry about is how much PAR energy you are putting into the tank. You should re-read the response given to you by Radik. Try using just 3, or 5, but most importantly, whatever rig you hook the lights up to, make sure that you use a dimmer that will allow you to reduce the lighting intensity when needed. You are paying far too much attention to things that don't matter one bit to plants, and are not paying attention the the thing that will actually destroy the plants in your tank. Plants do not really care whether your LEDs are red or blue, or whether the bulbs are for marine or navy. What they care about is that you avoid killing them with too much light, and it looks like that's what you intend to do. There is no optimal lighting level, period. This idea leads to a path of destruction. If I were you, I would be thinking more about how I intend to inject, diffuse and distribute CO2 into the tank because CO2 grows plants, not light.

Cheers,


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## wazuck (15 Oct 2012)

How about buying some 10w LEDs with drivers. It's a very cheap option at £4 a set. Just wire them up and hang them.


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## fleabilly (15 Oct 2012)

True I maybe off the deep end.
But not every light you look at has PAR readings.
When you ask they usually don't know.
And I really can't afford shelling out money for a contraption that will theoretically save me money by giving me an idea of how much light I need.

This is the website that I used to come up with my initial mad number...

http://fotohobbist.com/blog/lighting-fo ... -lux-what/

My tank footprint is 31.5 x 13.5 (inches)
According to the article. Multiply that (425.25) to get your surface area.
So say that I want to figure out what my total lumens are for a high light tank...
The low number (according to the article) of that is 28 LPI
So if I take my surface area and multiply that by the LPI that is how I come up with the mad number of... 11,907 lumens which I agreed is a mad amount of light.

Now at the moment I have co2.
But I am running 2 T8 bulbs and I am massively under lit.
Plants are turning yellow.
And I want to buy lights.
Hopefully LED's
But given that they do not all follow the standard of PAR.
Some say PAR is shite and that PUR is more important.
Most are grossly overpriced.
There is a lot of good deals on eBay, but again no standard to help me make a decision as to what I need.

I am in the deep end because I am willing to purchase lights,
But I have no real idea of what I need, because there, like I said is no real standard that will apply to LED and those who make them. Everyone will tell you that their product is the best.

Just wanting to make and educated decision,
And getting no where.

Cheers





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## Radik (15 Oct 2012)

They will not follow standards for PAR because they follow standard for Lumens  PAR is only for plant growers, nobody else in industry  Also LED with each new generation has better Watt to Lumens ratio (means also higher PAR per Watt). PAR is variable with tank height as well, so for 45 degree lens you get better penetration vs 60 degree lens. If you want to play around get cheap Seneye Reef with par meter, it will help you to understand lot of associations with light positioning and intensity etc.

So as me and Ceg told you get 5 bulbs and play around with them. You can skip dimmer if you can hang them from ceiling or some light arm.

PUR is impossible to measure so we stick to PAR. Each plant has own PUR requirements as I understand it. But PAR and PUR is linked.

Only standard I can recommend is CREE brand as it was tested and it works, other LED's are Osram Oslon but they are not so widely available.


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## ceg4048 (15 Oct 2012)

fleabilly said:
			
		

> True I maybe off the deep end.
> But not every light you look at has PAR readings.
> When you ask they usually don't know.
> And I really can't afford shelling out money for a contraption that will theoretically save me money by giving me an idea of how much light I need.


There are almost not lights sold with PAR readings from the vendor. This is a problem that all of us have. That is why we suggest that you get a dimmer, because that way you have some measure of control.



			
				fleabilly said:
			
		

> This is the website that I used to come up with my initial mad number...


So why on Earth would continue down that path knowing that it's insane?




			
				fleabilly said:
			
		

> Now at the moment I have co2. But I am running 2 T8 bulbs and I am massively under lit. Plants are turning yellow.


Yes, and plants do not turn yellow because they need more light. They turn yellow because they either don't have enough Nitrogen, or Iron or Magnesium. There is probably too much light and you are not taking care of them so adding more light will make them turn yellow faster. This is precisely why you are in the deep end. You are not asking the right questions and you have mistakenly assumed that adding more light will solve your problem when in fact it will only cause more problems.



			
				fleabilly said:
			
		

> And I want to buy lights. Hopefully LED's
> But given that they do not all follow the standard of PAR.


PAR is not a standard. It's an objective measurement of the amount of energy output by the lights.



			
				fleabilly said:
			
		

> Some say PAR is shite and that PUR is more important.


And those are the people who have algae and who have no idea how to get rid of it. If they paid more attention to PAR they would have less problems.



			
				fleabilly said:
			
		

> ...There is a lot of good deals on eBay, but again no standard to help me make a decision as to what I need.


What you need is to forget about lights and learn how to take care of the plants in your tank using the lights that you have, because your problems have nothing to do with lights.



			
				fleabilly said:
			
		

> ...But I have no real idea of what I need...


That's the first sensible thing I've heard so far.

Cheers,


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## copdodger (15 Oct 2012)

I use three par 30 led bulbs e27 fitting 10 inches above water surface great light output plus u get that shimmer effect ..


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## fleabilly (16 Oct 2012)

[/quote]Yes, and plants do not turn yellow because they need more light. They turn yellow because they either don't have enough Nitrogen, or Iron or Magnesium. There is probably too much light and you are not taking care of them so adding more light will make them turn yellow faster. This is precisely why you are in the deep end. You are not asking the right questions and you have mistakenly assumed that adding more light will solve your problem when in fact it will only cause more problems.

well then maybe try to help me with that then.
I know I am clueless in some areas. But I enjoy this, and I am seeking knowledge. Why else would I be here? I got a dosing kit from aquariumplantfooduk last week, and have been using that for two weeks. But not sure how long before i will see results from that. And yes now that you mentioned it, the yellow seems to be more in the light hotspots. (Which is one main reason I wanted lights in the first place, because of uneven light... Dark in the corners).



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## foxfish (16 Oct 2012)

The easy way to sort your lighting issues would be to go with the flow & use a suspended twin T5 lighting unit, one that can be moved up & down.
T5 lighting is a very reliable source of light that is used on thousands of successfully planted tanks.
I have been trying out household style LEDs for a couple of years now & have a tank running with 3 x 12w LEDs at the moment but I have found the LEDs not that good compared to a T5 because the 39w T5 seems to provide a much more even & brighter light source!
Of course you can find plenty of tanks running on LED lighting but in my opinion & experience they are just not as easy as using the old reliable T5.


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