Lighting - what's the difference??

Experts - what is the difference between the good quality "fish tank" tubes in 6500 K to a normal 6500 K tube supplied by eg Ellies. The reason I ask is that I saw a flourescent tube at Builders yesterday - 87 cm, 21 Watt, 6500 K for about R90 (internal balast supplied). Compare this to a balast and tube combo for about R230 from you LFS ???

 

@francoisve

Nothing aside from the price.

It's been widely debated by some and those that like to brag about the price tag associated with their purchase my differ from me, but from personal experience I can tell you that my plants really do not have an issue with the price tag and grows just as well under my Lighting Warehouse replacement tube as they did under the highly overpriced pet store edition.

 

+1 on DInky's comment. I use 4x 28w 6500k Oppel tubes.. R19 each and they work perfectly

 

I have been hunting out these tubes, where are you guys getting them??

 

Sent you a PM

 

Don't waste money on fancy tubes. Any tubes will suffice as long as they are in the 6500k-10000k range. Rather spend money on reflectors.

 

+1 for all mentions!!

IF you want to buy "good" tubes such as sylvania grolux for plant growth... then I would suggest the Lamphouse...

i have T5 tubes so 1.5m tubes is not that common at Builders etc....

Si I drive once every 2 years... buy a load of tubes for stock/backup...

 

Lightz by Greenstone shopping mall
Lighting warehouse, google for locations - Including Strubens valley
Lamphouse in Sandton area (best in my opinion, even stocks growlux for a mere R130 on 3 foot)
Voltex lights Randburg
Spot @ Hillfox in westrand.

Best is about 6500K -8500K

Name brand isnt a big issue here, I`ll replace every 6 months or so.

 

Jip I agree the shop lights can be just as good as some of the lps lights. @ABAB runs normal shoplight tubes on some of his planted tanks and some of his rotalla has red/pink leaves.
I personally prefer to look at the SPD curve of lights rather than the "K" Kelvin rating, but unfortunately not all company's have this info.

 

Whats the SPD Curve? @Good_Times

 

The spectral power distribution curve, it is represented on a graph and displays the visible colour spectrum intensity's produced at certain wavelengths measured in nanometers "nm".
Here is an example of the SPD curve of a Sylvania Gro-Lux Lamp.

It makes it easy to compare the intensity of the light at certain frequency's to that of the absorption spectrum of chlorophyll in plants.

Absorption of light spectrum by chlorophyll a & b

As far as I can gather Kelvin “K” in lighting refers to the overall appearance of the light produced. It is measured by the comparison of the colour of carbon at the same temperature of Kelvin. As to the composition of the light it does not really offer any information at all. Two 6500K lamps might appear the same to the eye in colour produced but the composition may differ. It’s still a good general guideline though.
It ranges from 2000K to 7000K and goes roughly from red at 2000K to orange, yellow white and then blue.

I might be wrong though.

 

So when looking at this. What do you look at?

 

Plants need blue and red light for photosynthesis out of the visible light spectrum, peaking roughly at 430 to 450 nm (blue) wavelength and 640 to 670 nm (red) (Nanometers). The rest they're not really bothered with. The green also falls somewhere in the 500's that plants don't use, so that is why a lot of plants appear green as they reflect this light.
So you would look for a light that peaks in the red and blue, but you don't want just those two peaks. The plants will love it and they will grow fine, but the tank will appear a purple/pink colour. These type of lamps you will usually see in indoor hydroponic setups where the main purpose is production and not aesthetics. Any other wavelengths produced will just be a waste of electricity/money in such setups.

Some aquarists do however buy pink/purple type lights, like Osram's Fluora lamp, for their aquarium as the main growing light and then just balance it out with some normal cool daylight "white" lamps for aesthetics.

Different colours have different specific wavelengths, but white light does not have a specific wavelength as it consists of a combination of different wavelengths, like sunlight that possesses all the colours of a rainbow.
So anyway what you would additionally look for (besides the red and blue) is some peak in the middle in the green 500's to even it out and produce a aesthetically pleasing white light.

 

Thank you, I understand now, and will be using your advice.

 

Thanks all for the info!!

 

here is some good info!

All bout light spectrum's and Nm for photosynthesis to take place, Lighting Spectrum and Photosythesis - Lighting - Aquatic Plant Central
LED colour chart. http://www.theledlight.com/color_chart.html

 

Hi lighting gurus

Have a 1ft that's going to have low to medium light plants in. Looking to do a 3w led light for it.

Now my questions are, is 1x 3w 180 lumen led enough or do I need 2, and is cool white the same as a 6500k and will be fine for the plants or do I need a warm white

 

Cool white is 5000-6500k.
3w should be good but 6w is always good to.