plant lighting

[FishKeeper-16]

Is actinic blue lights good for plants?

[happychem]

No, it's made for reefs. You want something between 5000K and 8500K. I like the 6500K, a nice, bright white.

[FishKeeper-16]

Yeah but the package says for freshwater tanks and my dealer says it will work but it can cause algea

[TKOS]

You will want a more full spectrum of light, which will include the reds and yellows to keep your plants happy.

Light does not cause algae, light can help algae grow in thepressence of excess food and carbon.

[Karnaaj]

Well by all means if your dealer says its good then it must be good :rolleyes: .Actinic is worthless for plants. You can use it in a non-planted tank but the fish look weird IMO. You can go up to 10,000k and still be good for plants.

[happychem]

I don't think that it's the case that actinic is worthless, it's just that actinic is a very strongly blue light. Plants absorb most heavily in the blue and red, blue light tends to make them short and bushy, which can be a good thing especially if you have a short tank, but it just doesn't look very good or natural in a fresh water tank.

[FishKeeper-16]

here is some detailed information on what one website says about the light bulb.

<<<<<<<<<<<<"When space is limited or if the aquarium needs a little bit more color, the Coralife 50/50 lamp is the lighting solution. The 50/50 provides the benefits of 6,000(K Trichromatic phosphors with 7,100(K Actinic .03 phosphors blended equally. The combination provides the versatility of two lamps in one package. Colors and clarity are enhanced and organisms dependent on light for photosynthesis thrive.">>>>>>>>>>>>

[Blinky]

AFAIK, actinics are used to provide a very specific nm range of light that benefits the indwelling algaes in some corals.
I've read that they can cause terrible algae blooms in FW tanks. The fact that they're designed to support the growth of certain algaes would make me wary of using these bulbs on a FW tank.

[FishKeeper-16]

Can my pleco eat the algea caused by the bulbs?

[happychem]

More than likely, but I'm going back to the earlier statement that light wavelength in and of itself doesn't produce an algal bloom. Yes, actinics are made specifically to target the coral symbionts, but I don't think that that means that they'll produce negative effects in freshwater. Plants also absorb in that wavelength so the algae must come from a nutrient imbalance.

On the other hand, it's probably a little on the low wavelength end of the spectrum, in other words, not taking advantage of all the wavelengths your plants can absorb.

Actinics tend to be more expensive than normal 6500K bulbs as well. That seems to be a fairly cold actinic though at 7100K. If you want to give it a shot, go for it. See how it looks and whether you like the results (both in colour and plant growth). If it's no better than a normal bulb, then you'll know.

[TONO]

Iam using one 18000k actinic bulb and it just causes algea problems, I am going to get rid of it soon. It doesn't do much for the colors of freshwater fish either, Just go with 6500k imo.

[FishKeeper-16]

Okay but the next time I purchase bulbs, I will have to pay carefull attention to the spectrum pictured on the box.