geministudios54

Newt. I think you're on to something!!! If you look at a GE gro-lux bulb for example, it too is purplish/pink to the eye but the kelvin rating is less than half the 9325k..You could be spot on!!..

GulfCoastAquarian

Color temperature isn't a marketing gimmick, but it is definitely misunderstood in marketing. The myth that "high kelvin" bulbs were blue came from a time when 3000K warm and 5000K cool bulbs were pretty much the only thing available. When 7100k actinic bulbs hit the market, it even further solidified the myth that "higher is bluer". Not true. Without getting into blackbody radiation, suffice it to say that it is a poor guide for picking bulbs.
You're not going to see bulb manufacturers marketing Photosynthetically Active Radiation specifications anytime soon, though!

Newt

I didn't say that color temp ratings were marketing gimmicks but rather the GE 9325K could be. Most bulbs that are marketed have a kelvin rating and most do not hold true to the black body locus line. In other words the actual kelvin temp of the bulb may not be what it is marketed as. They market it at a point that they think will make people buy them.

And Higher does have more blue light:

Cliff Mayes

I am using the GE9325s on a couple of tanks.

About a year ago, on the advice from a bunch of NET folk, I bought the AH kits and bought a bunch of the GE9325K bulbs for $14 a pop (I think from Atlanta.)

The bulbs do grow plants (some with pressurized CO2 and some with Excel) and the only comment I can make is that they make the tank look natural. I actually prefer the pinkish look but I want to grow plants.

imeridian

Here is another comparison photo series, this time using Current USA dual daylight 6700K / 10,000K lamps and the GE 9325K lamps.

This is 2x 6700/10,000K with 2x 9325K lamps:


This is 4x 6700/10,000K lamps:

turbomkt

That's a great comparison shot. I like the way it brings out the reds.

kakkoii

what about all glass 8000k 55 W bulbs, how do these look? http://www.drsfostersmith.com/produc...70&pcatid=8070

imeridian

kakkoii, I have one of those on the way (only one though - I'd need two to really show the difference in a photo), I will pop it in my fixture to make a comparison when it gets here.

kakkoii

KK...

imeridian

The 8000K AGA bulb arrived yesterday. It's not purple like the 9325K, it's very white, maybe every so slightly "cool" white, but I feel it fits the description supplied by AGA quite well: "noonday sunlight on a clear day."