caymandiver75

I currently have the 8000k CF bulbs in my All-Glass lighting. It looks good, but i'm not impressed with how washed out it makes the reds in fish. I just ordered some GE 9325 bulbs today, so hopefully I'll be happy with them.

gnatster

One way to look at the Kelvin figure is that it is a "sum" of the various wavelengths the bulb produces. Just as there are many ways to reach a total "sum" when adding a multitude of numbers the same Kelvin rating for various bulbs can have different spectral peaks.

With this in mind just because bulb A is 10,000K does not mean it will have the same spectrum as bulb B, also rated at 10,000K. Nor will both bulbs give the tank the same look.

DJKronik57

Thanks for your picture and feedback caymandiver! I agree that any one color temerature will have its benefits and drawbacks, and that mixing color temperatures is probably the best way to go in terms of looks and plant productivity.

The 8000K All-Glass does look pretty nice though, not too blue. Has anyone mixed this with a Coralife 6700K bulb? Trying to decide what the best combination would be. 9325K and 8000K seem like it would wash out the greens of the plants, since both tend to have large red and blue outputs and very little green. The GE 9325K bulbs I have did bring out the reds in the fish like no other bulb though. Post some pictures when you get the 9325K bulbs, I'd love to see them mixed if you have a dual bulb fixture!

Gnatster: Point taken, I was refering to the spectral output though, not the color temperature, i.e. the spectral output of the All Glass matches up with the most useful outputs for photosynthesis (and I'm assuming the ADA bulb comes pretty close as well, Amano wouldn't have it any other way).

mousky

I vote this thread as a sticky.

All this time I have been going off colour temperature alone, now with the help of you guys I will look more closely at the graphs on the box - Thank you

Rattail

Now this is one area I am really battling with.

Please tell me: is there a real difference between daylight Flourescent tubes one buys at the light shop and flourescent tubes one buys at an aquatic shop (LFS).

In South Africa, we pay a fortune for specialised aquarium tubes, so I'd be only too happy if "normal" daylight flourescent tubes will work as well.

I am told by the lady at the light shop that a normal Osram 3foot "daylight" fluorescent tube pushes out about 1500 at around 30 (something Watt. These will cost me R9.00 ($1.30) as opposed to between R110 and R180 for a Growlux at a LFS. (So you see my dilemma...)

(I am setting up a 1200mmx450mmx600mm (deep) aquarium) and intend using plants requiring moderate light).

Please help?

standoyo

Not sure about Osrams but I'm using Phillips 865's which does the job at a fraction of the cost. Plants are pearling, reds are red, greens are green and blues look brilliant. Nothing fake looking and best of all my camera white balance gets it right.

Skyfish

Standoyo do you have the exact model number stated on the bulb? I would like to try this one.

Cheers!

gf225

Great thread.

I've used T8 tubes from 3000K (Dennerle Trocal) upto a claimed 18000K (Hagen Aqua Glo). I had best results in terms of growth and attractiveness from 6500K that has 4 spectral peaks (Interpet Daylight Plus). They also had the greatest lumen rating (1300 for 24" 18w) compared to the Sylvania Activa 172 (6500K, CRI 98, 1000 lumen).

As discussed colour temp. and spectrums are independent. Using the Interpet and Sylvania 6500Ks as an example, the Sylvania appeared greener so suspect less effective for plant growth than the Interpet.

One thing I will say is that colour temps, spectrums etc. are less important the more physical qty. of light we have. Plants, IME can adapt to very different spectrums quite well so I now choose what suits my taste (rendition wise) and budget.

Being from the UK I don't have access the the popular GE 9235K and 10000K bulbs. Are these PC T5?

I'd like to try out the ADA 8000K T8s but they're 20mm shorter than the standard 18/20w T8 tubes so won't fit my unit.

ruki

From a statistical perspective it is an average, which is the sum you mentioned divided by the number of data points (or emission spikes).

Yes. This is one of the main weaknesses of the degree K rating of the bulb. Bulb makers should really include a spectrum chart on all bulbs that they give degree K ratings for.

ruki

The detailed answer is that all bulbs are different.

The not-so-detailed answer is that 5000K ("daylight") and 6500K ("full spectrum") bulbs at lighting stores will do a good enough job, especially when considering the high cost of high end speciality aquatic plant bulbs.

For advanced uses such as photography and show tanks, some of the specifically mentioned bulbs on this thread do a better job, but are usually more expensive than the "generic" 500K and 6500K bulbs.