# Blue Actinic marine lights promote brown algae



## Johnnyfishtanks (Apr 21, 2010)

so i have on for like few hours our more Blue Actinic marine lights. do they promote brown algae and other algae


----------



## Johnnyfishtanks (Apr 21, 2010)

anybody?...................


----------



## MadgicBug (Apr 22, 2010)

I don't believe it does. If I remember, brown algae are diatoms and usually cause when there is high silicas and\or something else (phosphate??). Possible nutrience imbalance.


----------



## gklaw (May 31, 2010)

I have two 65W CP running on 12 hours cycle and two 65W 10,000 K on shorter cycle. No issue at tall. If your water is dirty, does it matter what light you have when it comes to nuisance algae?


----------



## Captured Moments (Apr 22, 2010)

I don't think the blue actinic light will harm your plants nor will it induce algae growth. Plants use the whole spectrum : red end to blue/violet end. Apparently, a lot of the green and yellow is not used as much by the plants as compared to the red and blue end. 
Doesn't the blue light make it unatural to look at? unless you have it in conjuction with other spectrum bulbs and so it will not look so bluish. Algae in a planted tank is always present but it will break out if there is a trigger, such as when an imbalance occur. For example, you have a fluctuation in the Co2 level during the photoperiod, or not enough Co2, too strong a light given the amount of Co2 or nutrients, lack of nutrients.
You have 3 factors really: Light, Co2 or carbon source and nutrients (nitrogen, phosphate, K, micro elements).
If you have a healthy growth environment and balanced, usually algae is not a problem but if something happens that is not optimum to the growth condition of the plants then you are inviting algae to grow.
So, I would say there is no direct relationship between the actinic light and causing brown algae, but only as a possible indirect reaction to a chain of cause and effect with a bunch of other factors involved, either caused by you or by a change in the natural biotope of the aquarium.


----------



## MadgicBug (Apr 22, 2010)

I did some research on lighting awhile back and I hope I remember my info correctly.

The actinic light does little to nothing in a planted tank. I use one actinic out of four tubes in mine so it makes the fish looks nicer. The actinic is suppose to emulate the spectrum at 12 to 20 feet (don't know the exact number) of ocean water where alot of the red and yellow spectrums are filtered out. Corals and clams evolved to make use of that spectrum because of the type of algae that grows inside it that they feed off (symbiotic). water. The 10K is suppose to emulate direct sun near tropical regions (coral reefs) where it is more intense. Most of the aqautic plants in the trade are found in relatively shallow water murkier water (compare to crystal clear water of a reef)

I had 2 actinic and 2 10K spectrum in my tank and the plants were doing OK at best. Once I switched my lights to 1 actinic, 2 day light and 1 x 6.5K, my plants were doing much better and out competed the algae. CO2 (IMO) was the biggie for me.

As for the 10K spectrum, I think there is not enough red in it for plants as the output intensity spectrum is too narrow. 

Someone had posted a chart on lighting spectrum and the tube output that plants do best in.


----------

