# actinic light for a fresh water tank



## F22

Actinic is worthless for plant growth, but can help in a fish only system, it really makes the colors pop out on the fish. It should only be used in a twin bulb fixture. Makes african cichlids, barbs, glow danios all look amazing.


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## kcirtappatrick

So that being said..if i have 1 24w bulb and 1 24w actinic bulb. i actually only have 24w for plant growth?


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## Darkblade48

kcirtappatrick said:


> So that being said..if i have 1 24w bulb and 1 24w actinic bulb. i actually only have 24w for plant growth?


Correct.


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## kcirtappatrick

hmm. well good thing i didn't buy that one yet haha thanks for the advice guys!


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## Hoppy

First, the phrase "actinic" applied to fluorescent bulbs means different things to different bulb manufacturers. So, it may be that some or even many "actinic" bulbs provide most of their light outside of the wavelength range that plants can use. But, it may also be that some, if not many "actinic" bulbs provide a substantial amount of blue light within the range used by plants. So, I'm still not convinced that "actinic" bulbs are useless for plants, but in my opinion they do make the aquarium look terrible.


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## mordalphus

I agree, although most of the light may be in an inaccessible wavelength, there's no getting around emitting a broad spectrum through fluorescent light.


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## ReefkprZ

420-460nm (the range of actinic light) wavelength can be used by both plants and algae (there are forms of algae that adapt especially for this reason) for photosynthesis. the amount of benifit would definatly be very debatable, I would say somewhere around very little benifit. and most likley algae being the more adaptable life form to lowerlight condition would reap the greater benifit. But I was witness to an expiriment where both corals (with symbiotic algae) and Eelgrass (_Zostera spp._) (a true marine plant, not a macro algae) where grown under nothing BUT actinic light it didnt grow fast but it did grow. the corals fared far better.

water blocks red wavelengths of light and allows blue light to travel the furthes. I can only hypothesize that deeper water plants would have a better chance of utilizing the light, but maybe not. I do know in corals, different strains of zooxanthellae specially adapted to the light situations gain dominance. in plants it may just be that they are better at using what little light there is.


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## hbosman

I have two actinic bulbs that I have never used, never even tried to see what they would look like over my aquarium. Maybe I should put one in and see what algae I can grow. :biggrin:


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## ReefkprZ

I know from expirience (please dont asxk what possesed me to do this) if you put 4x96w of 50/50 (half 10k half actinic)powercompact over a 60g freshwater goldfish tank, with no plants or co2, the green waterbloom is pretty damn spectacular. I'm talking a solid green cube of water. :icon_eek:


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## hbosman

ReefkprZ said:


> I know from expirience (please dont asxk what possesed me to do this) if you put 4x96w of 50/50 (half 10k half actinic)powercompact over a 60g freshwater goldfish tank, with no plants or co2, the green waterbloom is pretty damn spectacular. I'm talking a solid green cube of water. :icon_eek:


I bet! I've had a few vicious greenwater blooms when I got to ambitious and uprooted and moved to many plants at one time. The fish seem to like the greenwater but, the wife didn't. :biggrin:


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## NJAquaBarren

I upgraded to a 4 bulb fixture recently. Use 1 bank of 2 bulbs to run the geissemann midday and aquaflora that I had been using and in the second bank, 1 aqua flora and 1 of the actinic that came with the fixture. I split the banks during the day with an hour overlap with the flora/actinic for the afternoon/evening period,

I loved the look of the flora/actinic combo. It was a little dimmer than the other two bulbs, which I liked at night, and the colors of fish and plants really popped.

After a month though Plants were showing some serious decline. Can't say that the lights were the source, but obviously a fundamental change in the setup. I've returned to all midday/aqua flora and increases fert dosing for now and things are recovering.

Miss that look in the evening though.


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## Sharkbait-ooHAHA

What's the difference between an actinic and using a 10k or an 18k? Would those lights have any effect?


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## Hoppy

Fluorescent lights don't have a true color temperature, which requires that the bulb emit a continuous spectrum. So, some manufacturers assign a color temperature to their bulbs, which they think approximates what color temperature the bulb would have if it did have a color temperature. But, some manufacturers also assign a color temperature to their bulbs that they think will make the bulb sell better - probably a majority of the bulbs. So, a 10,000K bulb is a very white light, that tends to look a bit bluish. An 18,000K bulb is a bulb the manufacturer wants you to believe is twice as good as a 9000K bulb.

The only sure way to find out how good a bulb will do as a plant bulb is to carefully test it, first measuring the PAR it produces at the distance you want to use it, and next measuring how well it grows plants compared to another bulb that produces the same PAR reading.


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## TheVisionary78

I use a single 55 watt compaq actinic light bulb at night time for late evening viewing in my living room. My tank gets 12 hours of 50/50 6.500 and 10,000k 110 watts during the day. I have no proof that actinic benefits the plants. In fact I believe they are using O2 when I use it at night time. It makes my freshwater inverts look awsome. Kind of like moonlight.


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## Sharkfood

I've run those 18,oooK bulbs before. When I initially set up my first planted tank, I ran those solely as the guy at the LFS told me they were best for plant growth (He was mistaken). Plants still grow under them, but they're purplish (AKA weird looking) and they don't appear to be nearly as bright as 6700k or 10,000K bulbs of the same brand.


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## IWANNAGOFAST

wow spam, wth


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## lauraleellbp

IWANNAGOFAST said:


> wow spam, wth


Got em, thanks- spammer go bye bye! Next time just click on "report post" roud:


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