varying bulb types in a reef aquarium

[drew11588]

Hey fellow reefers. i have a 24 gallon jbj nano cube which has 2 x 36 watt 50/50 (10kk/ actinic). ive read that actinic bulbs are in the good range for coral photosynthesis. my question is will it benefit the corals i have in my tank if i switch out one of the 50/50 s for an actinic bulb? or do i want the white and blue light in equal amounts?

 

[drew11588]

forgot to mention its compact fluorescent

 

[baldyguy]

I am not an expert, I am sure on this site there will be one, but the lower the Kelvin the yellower the lighting looks but allows fast coral growth........so high K rate slower growth looks good with the colours etc if you have 10k bulb will aid growth the actinic will give the colour........personally I would leave it if it looks nice and corals are fine leave them on

 

[crb530]

i have two 65k how will that work with corals

there 25 wats for a ten gallon tank

 

[baldyguy]

is the 65k actinic ones?

 

[crb530]

no they are 6500k mini compact

 

[baldyguy]

I would leave the actinics where they are then and try and find a 10k variant for your white light........... only to help your coral growth......6.5k are okay and if it's working then leave it as is............

 

[melosu58]

I personally think actinics are needed in the reef aquarium. You know the blue part of the spectrum is what penetrates into the ocean to the corals. Liveaquaria says " Actinic Bulbs - Emit light predominantly from the blue end of the color spectrum. Recreates light conditions found in deep water and provides the light energy necessary for proper photosynthetic coral growth. Actinic bulbs are ideal for reef aquariums."

 

[SparKy697]

There always seems to be more to read in this hobby. This topic is no exception... I found these articles interesting, maybe you will too.

Advanced Aquarist's Online Magazine - Feature Article: Coral Coloration and Incident Light: A Photographic Essay

Advanced Aquarist's Online Magazine - Feature Article: The Best Lamp Is...

 

[ccCapt]

The 1st link you posted is a great article by my friends Sanjay Joshi and Ken Feldman. (Ken will be speaking at MASNA in Atlantic City this summer on organic carbon and protein skimming in case anyone is going) In a nut shell, what that article says is the reason corals look different under different kelvin temp bulbs is because the corals reflect the color of the bulb. The bulb does not give the coral more or less color. So a coral grown under 20k lighting might look more colorful than a coral grown under 10K lighting, but take both corals and put them under the same light and they look the same.

But back on topic, actinic lights are basically eye candy just to make the corals look more colorful. A full spectrum 10K bulb has all the blue light needed for photosynthesis.

 

[drew11588]

so theres really no downside to increasing the ratio of actinic: 10,000 k bulbs? besides it looking bluer...

 

[melosu58]

I personally think they are needed in the reef tank. I stated my reason above.

 

[ccCapt]

so theres really no downside to increasing the ratio of actinic: 10,000 k bulbs? besides it looking bluer...

The down side is actinic bulbs have very little PAR. Replacing 10K's with actinics cuts down on total PAR. Depending on the corals you have, it may or may not make any difference in growth.

There are many reefs run with NO ACTINIC lighting. Here's 1 at PSU.

 

[thincat]

Like Mike stated I to believe some actinics are needed in 420-460 range. Yes they don't have as much PAR as a 10k so it all comes down to the simple fact....Does it look good to you...and are you satisfied with the growth of your corals..

 

[melosu58]

And I`m not in no way arguing with Larry. He`s one of the best but this is one of those that we have two different opinions which is good for the hobby. If there was one right way to do things we would all be doing it.

 

[ccCapt]

I know Mike. Not arguing with you either, but it is a fact that a 10K full spectrum bulb has all the blue light needed for photosynthesis....at least if you believe all the research done by Sanjay and his associates. You can see the size of the corals in that PSU reef. It's run on 10K metal halides only. That being said, I do run actinics for the the color (VHO actinic is the best actinic).

 

[thincat]

So VHO actinics...Make sense. Not worrying about penetration since Actinics go deep anyway...just not as strong. So you use it as "eye appeal"?

 

[Innovator]

cCapt is correct and actinics have always been used throughout the hobby mainly for aesthetic reasons (drowns out yellowing); however, I believe according to Sanjay some of the highest par halide bulbs these days are in the 14k-20k range which is aesthetically similar to actinics.

 

[melosu58]

That being said, I do run actinics for the the color (VHO actinic is the best actinic).

That might be where we are differing at because I`m talking VHO and I guess you are talking MH`s. I have no experience with MH`s. So is what you are saying Larry the same for all lighting or just MH`s?

 

[HN1]

I just gotta say thanks to the OP for starting this thread and thanks to the major participants. I've learned a ton about lighting in this thread and subsequent curiousity induced reading. Keep up the discussions! I'm sure I'm not the only one getting value out of lurking along.