Light Spectrum 10K or 6.7K

easterly: check out Rex's guide on light.

In all honesty, the plants don't care. It just a preference on what you like to look at. Some say 6500k alone is too yellow, other say 10000k is too blue. I would just mix 'em up for now and adjust from there.

I agree, it's personal aesthetic choice. 10000K is a bit too bright/intense for me, so I tend towards 6500K. Plants should do about the same under both lights.

I think i will get 6.7K/10k blubs then

In europe we use mostly 4000 to 5000K and top out at 6500K but depends on how you wish your tank to look like.

I'm running 6700k/10000k current usa slimpaqs now, and they are nice. It is a wee bit too crisp/dry for my tastes though. The bulbs are fairly new so I'll let them burn in a bit before I make a judgment. I think I'll get a pair of something in the 4000k range and see how well it looks with the 6700s.

I'm running 6.7K's... I've tried 10K's and prefer the 6.7K bulbs.

If you're really undecided, just buy both and try them individually to see which you prefer. You can keep the extra as a spare bulb in case of any emergencies.

A mix of both 6700k/10000k looks really crisp ice blue like.
I prefer ADA's 8000k which is a nice white color and doesn't make the plants look fake.

But I have no problems with 6700k....7000k is nice too.

Of course, the K number is something of an average of the reds, greens and blues from the light, as the human eye/brain interpretes them. It's an approximation so multiple spectra can average out to the same K number. But it's better than nothing... (^_^)

I have 6700K over my tank. It looks good and the plants are constantly pearling.

ruki said:

Of course, the K number is something of an average of the reds, greens and blues from the light, as the human eye/brain interpretes them. It's an approximation so multiple spectra can average out to the same K number. But it's better than nothing... (^_^)

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Aye. I've been trying different bulbs lately and the best combo so far is Current USA 6700k "daylight" and Geissmann 6000k "midday". 700k color difference wouldn't seem like much but the Current bulbs are really more blueish, I think they are targeted to reefkeepers for the most part. 6700k may be correct but its a blue 6700k IMO.

I have some more bulbs coming in, GE 5000ks. I will be playing around with combos of each. Also have Current USA 10000k so I can come up with quite a few combos.

Really digging running Geissmann 6000k in the morning and evening and noon bursting Currents 6700k/10000k. When all four run it seems to give a very balanced light, but still has blue and red punches, hard to really gauge until I get some more fish in the tank. I've been bobbing different colored items in the tank for color testing lol.