# question about bulbs in regards to photosynthesis



## Mferko (Jun 8, 2010)

so i read the sticky on lights and it seems like 6700k is better for plants than 10k, but what about actinic bulbs? says on the box they encourage photosynthesis and i know plants generally love the blue/red wavelengths for photosynthesis and the sword fern in my 37G seems to be doing better since switching to a double lamp fixture with 1 10k and 1 actinic bulb

what do you guys think? provided you like the looks of the blue light in the tank, is it also good for growing plants? 

i currently have the same 2 light combo in my planted biocube14 and was wondering if i should change it a bit

thanks,

mike


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## Johnnyfishtanks (Apr 21, 2010)

i was growing plants with 15k bulbs and my plants and fish looked better


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## tang daddy (Apr 21, 2010)

if its plants 6500k to 10000k is fine, but anything more is not as benificial for plants, even saltwater algae or macro algae use 6500k for optimum growth. 

Corals are a different story as they live in greater depths of the ocean light is diffused so that's why 15k lights and 20k are more common for Corals!


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## effox (Apr 21, 2010)

Like Chris said above, actinic bulbs are for corals... otherwise aesthetic purposes to colour the tank that nice glow in FW applications.

I think you'll find that if you replace your actinic bulb with another 10,000k you'll have too much light and will have algae problems. You could remedy this with less light hours I suppose, but then you can't view your nice fish setup as often. Personally, after doing this I went back and replaced the actinic as there was way too much light, albeit this was a 29g with more wattage than the 14g so who knows.


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## Mferko (Jun 8, 2010)

cool i'll leave it as is


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## CRS Fan (Apr 21, 2010)

Straight actinics are useless for Freshwater planted tanks. Although they can be used as a nightlight. I used to run my 29 gallon tank with 3-6000K Midday bulbs and 1-Aquablue+ (14,000K). This was 4 Geismann bulbs in a 4 X 24W T5HO fixture. Excellent growth and it balanced out the white from the 3-6000K bulbs.

Best regards,

Stuart


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