Cheap full-spectrum lighting (UK)

[oldwhitewood]

Personally I like the look of the Arcadia Overtank Luminaire. They do a 32" 4 x 24W T5 that would be perfect for my Rio 125. I'd use 6500K tubes.

I've seen them for about £160. mmmmm.......Christmas soon!

can you get the luminares without tubes though as apparently the plant pro tubes are a horrid colour. What tubes would you partner the luminare with?

 

[donkey]

Hi .
i have two plant pro tubes over one of my tanks and i think the colour is good to be honest if your not going to use the plant pro tubes what other make tubes were you thinking about using

 

[George Farmer]

Personally I like the look of the Arcadia Overtank Luminaire. They do a 32" 4 x 24W T5 that would be perfect for my Rio 125. I'd use 6500K tubes.

I've seen them for about £160. mmmmm.......Christmas soon!

can you get the luminares without tubes though as apparently the plant pro tubes are a horrid colour. What tubes would you partner the luminare with?

Jason Scott, owner of The Waterzoo and writer for PFK told me they were around 6500K but a little on the expensive side. He recommended the 6000K D&D T5 tubes.

I've read ads in PFK noting that they sell the units without tubes.

 

[oldwhitewood]

Hmm, it might be something to investigate then, it makes sense that they might not also come with tubes actually.

 

[Dubby]

Thats a good link GF. I do note that the Activa 15W tube gives off only 700 lumens as compared to (say) a GE Polylux 15W which gives 1000 lumens.

 

[George Farmer]

Thats a good link GF. I do note that the Activa 15W tube gives off only 700 lumens as compared to (say) a GE Polylux 15W which gives 1000 lumens.

Interesting point Dubby.

The GE Polylux tri-phosphor T8s are higher intensity but I believe they have a lower K (around 4000K) and lower colour rendition index (CRI) at 85.

These two factors combined would probably make them less effective regarding plant growth. I’ve done a bit of research regarding CRI and it is believed that this may be more important than we give credit. If a tube has a lower CRI then its K rating claim will likely be inaccurate.

For those unaware of CRI –

“Colour rendition refers to the quality of the reproduction of colours under a given illumination. The degree of colour distortion is indicated using the colour rendition index. A comparative light source with continuous spectrum serves as a reference light source, whether this be a temperature radiator of comparable colour temperature or the daylight.”

So basically the higher the number (up to 100) the better.

I would say that a tube with 6500K and very high CRI (>90) will give the best results where plant growth is concerned.

 

[Dubby]

Thats interesting to know about CRI affecting plant growth. Do you have any more info on this?

My understanding has been that ......CRI is a measure of what the human eye sees in terms of true colour. Therefore its not what the plant sees and hence you'll find that most plant bulbs have poor CRI ratings.

The factors that that I look for (based on my lil research ) are PAR (photosynthetically active radiation), Lumens and the Kelvin rating (to a smaller extent).

I have compared the pearling of plants using a 'Daylight' tube with 5000K and a tube with higher lumen but lesser 3000K rating. The tube with higher lumens gets my plants pearling faster.

 

[George Farmer]

In hindsight you are probably correct about lumens and PAR being more relevant in planted tank. My research was based on terrestial plant lighting where obviously you do not get the light alteration properties of water that one finds in aquariums. This would explain why CRI does not have much influence on submerged growth.

However I would still choose these tubes as the overall colour would look more natural and any growth rate difference I would assume would be secondary assuming there is enough output (I'm talking enough light to utilise CO2 injection).

As with most things it is down to personal taste, budgets etc. One thing I have learned in this hobby is that there are many ways to acheive very similar goals, one way is not necessarily better than the other, even if someone swears by it (I am guilty of that myself.) Lighting is a very complex subject and one I am still very much in the dark about.

 

[ChrisP]

Anyone know what temp the 30W tubes are on http/www.firstlightdirect.com Direct link to the ones I am looking at is here. http/www.firstlightdirect.com/pp/Fluores...ite_Colour.html

 

[George Farmer]

Extracted from the .pdf link on the site.

colour temp. 3450K and CRI 54.