PL Lights vs Flourescent

[tetra]

Hi,
I was confused after talking with different LFS owner. Which type of lights are better?
Is PL light better than Flourescent lights for plant tank?
Someone said that PL light is too hot, and its intensity will reduce after a few months etc.

Any advise is appreciated!

[bclee]

PL just provide more wattage in a smaller package... not too different from FL.

36W PL is about the same size as 15W FL... of course a 36W will emit more heat.

BC

[tetra]

So, does that means if I have space constraint, I will choose PL over FL?

[madans]

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On 12/5/2002 11:50:33 AM

So, does that means if I have space constraint, I will choose PL over FL?
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Yes, you should. A 36 watt PL will take up roughly 18" along with the holder. I find them convenient for a 3 feet tank as I need to use just three of them evenly spaced front to back to have uniform lighting throughout the tank.
PLs are better when you want to grow high light stem plants. You can plan your planting and place the Lights where you need them in a DIY lighting setup.
PLs are rumored to loose their intensity but the manufacturers claim otherwise. i have had the same bulbs in use for a year now without any problems.

Madan Subramanian
Bangalore, India.

[vinz]

PL intensities are suppose to last longer then FL.

[tetra]

Hi all,
Thanks for your comments.
So for a 5x2ft tank, which PL should I be buying and sufficient for plant?

[tetra]

Hi all,
Thanks for your comments.
So for a 5x2ft tank, which PL should I be buying and sufficient for plant?
Are there 5ft lenght PL light?
Any suggestion?

Also, does anyone knows how to calculate the amount of lights required for tank base on the size of the tank?

[tawauboy]

pl light comes in 3 wattage rating. 18w, 36w and recently 55w. the lenghts are approximately 24cm for 18w, 42cm for 36w and <60cm for 55w(not sure as i have not used one). so there is no 5' pl.

as for the amount of light required for you tank, it depend on the light demand of the plants you are planning to keep. most use the guide, 2w/gallon for low light plants and up to 3w/gallon for high light plants.

to calculate, calculate the your tank's volume using cm. divide teh volume by 1000 to get volume in litres. then divide the litres by 3.785 to get x us gallons.

[Alfa Low]

[quote]
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On 12/6/2002 2:01:59 PM

pl light comes in 3 wattage rating. 18w, 36w and recently 55w. pl.


There are 6w, 9w, 11w, 13w, 24w, 27w and 96w as well.

[tetra]

Tawauboy, thanks for the tips. Based on my 5x2x2 tank, I have calculated, I briefly need need 351 watts, which means I need 9.75 of 36 watts PL lights - 10 PL. Is this correct? 10 PL for my tank! Not sure can fit on the top??

Can anyone recommend where should I get the PL lights for reasonable price? This will probably cost me a few hundreds $, I think. Please recommend reasonable LFS!

[tawauboy]

Alfa,

thanks for the correction.

[vinz]

Tetra,

I have 12 x 36W PL on top of my 6 footer. All contained within 2 light sets, 2 rows of 3 in each set, takes up about half the top of the tank.

Anyway, you might want to consider:
- 6 x 55W tubes? (330W)
- 4 x 55W + 4 x 36W (364W)

[tawauboy]

Vinz,

did you buy the lights of the shelf or designed by you but built by someone or diy?
are the lights perpendicular or parallel with the front glass wall?

[Allen_1971]

Tetra,

I know you are asking about PL and FL, but have you considered MH? The initial outlay is higher than PL/FL, but the cost of maintenance is cheaper. For a tank your size you probably need 2 x 150W MH and it should more or less to the job.

I'm not sure what the cost of MH bulbs are, but you can work out the cost yourself... 2 MH bulbs every 2-3 years vs 10 PL tubes every 6-9 months.

[tetra]

Vincent, Your suggestion is reasonable but I am not sure with these combinations, will the lights get distributed evenly into the tank.
How to place (4 x 55W + 4 x 36W (364W)) so that the whole tank gets the light evenly.

Allen, May I know where I can check out in the LFS of the MH light? Or anyone know the cost? 2 x 150w = 300W, what if my tank need a bit more wattage for strong light plant, how can I increase the wattage eg. 350w?

[Allen_1971]

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On 12/9/2002 9:17:11 PM

Allen, May I know where I can check out in the LFS of the MH light? Or anyone know the cost? 2 x 150w = 300W, what if my tank need a bit more wattage for strong light plant, how can I increase the wattage eg. 350w?
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MH is pretty powerful as a light source, and I would venture to say that it is more efficient than FL. Remember W/gallon is a guide, a better guide would be LUX or lumens/m^2. Also, given that MH is more efficient, you actually get more lumens/watt than FL and PL. So you probably do not need as much watts. Light penetration is also better with MH... The only downside with MH is heat... so you would need some cooling solution like fans or if you have $$$$ then a chiller.

As for prices, I've really been out of the scene for some time, so I can't help there...

[chris]

Hi!

I need some info about MH... the sites I visited did not provide much info.

1)For a tank 36 inch by 16 inch by 16inch... is 1 MH 150W enough, assumming I want to keep light-loving plants?

2)How to mount a MH?

Thanks.[]

[vinz]

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On 12/9/2002 5:17:05 PM

Vinz,

did you buy the lights of the shelf or designed by you but built by someone or diy?
are the lights perpendicular or parallel with the front glass wall?
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Tb,

I got the two 6 feet FL sets (JBS brand, I think) 2nd hand with my 6ft tank. I DIY converted them to PL.

They sit parallel to the front glass.

[vinz]

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On 12/9/2002 9:17:11 PM

Vincent, Your suggestion is reasonable but I am not sure with these combinations, will the lights get distributed evenly into the tank.
How to place (4 x 55W + 4 x 36W (364W)) so that the whole tank gets the light evenly.
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Simple. Most lights sets will be able to accomodate 2 rows of PL. For each set, have one row of 2 x 55W and one row of 2 x 36W.

[zac08]

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On 12/9/2002 1:21:12 AM

Tawauboy, thanks for the tips. Based on my 5x2x2 tank, I have calculated, I briefly need need 351 watts, which means I need 9.75 of 36 watts PL lights - 10 PL. Is this correct? 10 PL for my tank! Not sure can fit on the top??


Can anyone recommend where should I get the PL lights for reasonable price? This will probably cost me a few hundreds $, I think. Please recommend reasonable LFS!
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Eh...if yours is a 5ft by 2ft by 2ft...it should come up to 149 gallons. This is done basing on this calculator from Arofanatics : http://www.arofanatics.com/articles....ent=calculator

Say you fill it to 90%, it'll be about 135 gallons. You'll need about 405 watts. And if using 55w tubes, you'll need 7.36 pcs... so about 6 pcs of 55w with 2 pcs of 36W would suffice for your tank.

And for arrangement, I'd try it in a 3 - 2 - 3 formation.... First row, 55, 36, 55...second 55, 55... third row, 55, 36, 55.... But opinions may differ from others...just my idea..

Do check out the prices from shop to shop. But from what I figure out, you can try Nature Aquarium. Their prices seem to be the most competitive. And if other forummers have a better price, please do inform the rest of us here.....