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actinics needed with metal halide? (1 Viewer)

Myclang

Myclang

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I set up my 180 gallon with the notion that actinic VHO's/T5 were not needed for, but an aesthetic, because most hobbyist would use a 65k to 10k bulb which is too yellow and then supplement the actinics in.

I run 20K radiums, and I love the blue they produce, but I know that high of kelvin, there's a lot of wasted spectrum. I was reading that actinic lights actually do produce a good usable spectrum for corals in the 420 nm range. Is this true? should i be rethinking the design of my lighting setup? I really couldn't find a good answer, if actinic lighting is truly needed for healthy coral growth, and color.
 
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That's a good write up of how the Radium bulb itself works, but it doesn't answer my question on how the VHO/T5 bulb may or may not play a roll in usable light spectrum, or if i need actinic supplement or not.
 
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Need? No. Want, maybe. Symbiotic zooxanthellae mainly use chlorophyll a and c and carotenoid pigments. You have a very strong absorption in the 450nm range (within a wide band around that, just going off memory here) so you want some blues but your metal halide bulb may already provide that. Have to check its spectrum to know for sure I guess.
 
patent said:
Need? No. Want, maybe. Symbiotic zooxanthellae mainly use chlorophyll a and c and carotenoid pigments. You have a very strong absorption in the 450nm range (within a wide band around that, just going off memory here) so you want some blues but your metal halide bulb may already provide that. Have to check its spectrum to know for sure I guess.
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Thanks Patent, thats what I figured with the metal halide setup I had. I know that the farther I move up the spectrum the slower the growth may get, but I was getting mixed answers on the actinic portion. I've been kicking around moving down to a 14K. the Radiums, and even the ushios i've used in the 20K spec may be a bit overkill on the blue.
 
What ballast are you running? 250 or 400w bulb?

Personally what I am doing on my build in progress is running 250w bulbs on an up-to-400w Luxcore ballast. This gives the option of burning them at 245w ("250w") or 300w ("250w HQI") so I can choose bluer with less PAR or whiter with more.

IMO, one of the most important things a supplemental light has to have is versatility (beacuse I'm finicky when it comes to color). VHOs, while they can provide a classic actinic look, hardly have any other color options. T5s are going to cost $20+ for each bulb if you want to try out a different color.

I have chosen to go with LEDs. Even if its just some simple DIY panels running on dimmable ballasts with potentiometers, you have much better control of the color and spectrum you want. If you ever get a feeling that the tank needs more 420nm, then you can just turn up that channel.

Its going to come down to personal preference whether you like bluer or whiter. If you want to have that actinic spectrum, but more of a whiter look, look into 50/50 bulbs like UVL Actinic White. It appears white but has some actinic underneath.
 
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I used to use 400 W Iwasaki 6500 MH bulbs all the time, on some systems without any actinics. This was back when my tanks were SPS dominated, and when I had a student doing a research project on Acropora colony development. The corals grew GREAT. SPS corals, LPS, soft corals, rose anemones, zoanthids, etc. I had spectacular coral growth back then. Colors of some of the corals developed better than in some other people's tanks (e.g. the hot pink birdsnest coral I used to have).

If you want to see nice fluorescence, or a bluer look overall, then you need actinics, or a bluer metal halide bulb, or some LEDs or something like that. But you absolutely don't need this for excellent coral growth.
 
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I have all galaxy electronic ballasts that go up to 250w plus a HQI setting for higher wattage burning. I think I'll replace my radiums with a nice single ended 14K bulb and see if I like it better. I was getting decent growth out of the Radiums, but stuff was definitely not growing as fast as it should.
 
With a galaxy ballast 250w single ended should have no complaints about growth. Of course when your tank is nothing but frags there it give the appearance of slow growth but in perpective to coral size it's probably growing at fine pace. A 4" coral with hundreds of tips and each tip grows 1/4" will look like its growing faster becuase all tips are growing vs. a little frag with 1 or 2 tips and the same 1/4".

There is so much other things that can have a big impact to growth that I'd probably be looking more towards tank maintenance, water parameters, water clarity more than I would your lighting.

But as Capman mentioned, if you want growth and willing to sacrifice color, 6.5K Iwasaki is the grow king ! Many years ago I gave Agu a frag of my ( what they call a scripps acro now days ). I ran 10K Ushio 400s he ran 6.5K Iwasaki, His frag outgrew my whole colony in 2 years time. Of course lots of variables than just the bulb since different systems and also take in consideration that his colony for the most part was brown and mine had better coloration but if growth you want.
 
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If I had a canopy, I might have thought about going back to the good ol' days of 65K. since I could incorporate some VHO's, simple reflectors, and sockets into the hood. As of now my tank is open, but I've been debating on having a canopy built. I've had my nieces and nephews and god son over, and I'm always so worried about them being blinded by the halides.

You're absolutely right on tank maintenance, and params affecting the overall growth. It just seemed that even with nearly undetectable phosphates, and untraceable nitrates, that my corals still didn't have that color pop that I'm looking for. Not an aesthetic pop, but the coral overall had a "duller" appearance, so this is where I was curious if that actinic spectrum actually is beneficial.
 
It just seemed that even with nearly undetectable phosphates, and untraceable nitrates, that my corals still didn't have that color pop that I'm looking for. Not an aesthetic pop, but the coral overall had a "duller" appearance, so this is where I was curious if that actinic spectrum actually is beneficial.
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The correlation between nutrients, alk, and light intensity are a big factor in color. Stripping the tank of all PO4 and NO3 isn't going to necessarily give you the best color.
 
Kepler said:
The correlation between nutrients, alk, and light intensity are a big factor in color. Stripping the tank of all PO4 and NO3 isn't going to necessarily give you the best color.
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I guess I'm confused... I thougt that's what the point was? I'm running an algae scrubber, skimmer, and some activated carbon for polishing. how should I rethink/ rework what I'm doing?
 
Myclang said:
I guess I'm confused... I thougt that's what the point was? I'm running an algae scrubber, skimmer, and some activated carbon for polishing. how should I rethink/ rework what I'm doing?
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If you have washed out colors and have very low nutrient levels (and bright lights), you may want to just feed the fish more. More food through the fish = more food to the corals. This will also eventually raise the PO4 and NO3 a bit with the added bioload. Fine tune it until you hit the sweet spot. If you go looking through tank of the month write ups you will find that a lot of succesful tanks hang around 0.02-0.05 PO4 and 1-5ppm NO3. High alk tanks may even have even higher nutrients. Pretty sure David mentioned that he keeps his PO4 at 0.07 or so (correct me here if I'm wrong) which gives a richer look to the corals.

Put loosly, it works something like this:
Pale coral - not enough zooxanthelae (low nutrient, bright light)
Brown coral - too much zooxanthelae (high nutrient, dim light)

Its easier to fix the pale coral problem since in most cases you would have very efficient filtration, so the tank can handle some more food (in moderation), without causing issues.

A guy over on R2R with a very successful tank mentioned "You can't over skim, you can only under feed". He ran a skimmer rated for 500g on a 30g tank and fed tons of frozen food daily. The colors really popped in his tank.

Check out this thread: http://www.reefcentral.com/forums/showthread.php?t=2253547
 
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hrmmm... alright. that makes total sense. I initially was over feeding, which was causing some massive po4 issues, which led to a lot of cyano. now that the algae scrubber has taken off, i should start feeding more. alright i'll try that and give it a month or so and see how far i need to go. i know my scrubber is rated up to 24 cubes, I don't even think I'm feeding a cube a day at this point, because of how much problems i was having.
 
If the scrubber turns out to be too efficient you may be able to reduce the photo period to an extent (just not so much that it is detrimental to the algae screen).
 
Kepler said:
If the scrubber turns out to be too efficient you may be able to reduce the photo period to an extent (just not so much that it is detrimental to the algae screen).
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since I'm feeding so little right now. I think I'll start ramping up the feeding and monitor growth, and back the lights on the ATS if the algae starts to brown out on me. thanks for all your help. It's easy to start over looking things.
 
Myclang said:
since I'm feeding so little right now. I think I'll start ramping up the feeding and monitor growth, and back the lights on the ATS if the algae starts to brown out on me. thanks for all your help. It's easy to start over looking things.
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No problem. Just remember to take it slow since bacteria and algae will have to catch up to the additional bioload.

I found this post interesting. There's no chance anyone would ever feed this much, but it puts it into perspective what the average coral is getting for food daily in the wild. This is most likely how they keep their color and growth up even though the water chemistry is lower than what we consider to be ultra low nutrient.

http://algaescrubber.net/forums/sho...d-(used-to-be-5)&p=12142&viewfull=1#post12142

(Post #30)
 
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Kepler said:
No problem. Just remember to take it slow since bacteria and algae will have to catch up to the additional bioload.

(Post #30)
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I don't know what sort of algal turf scrubber is being used here, how large the tank is, what is being fed, etc. But an algae turf scrubber that is completely colonized by good sorts of turf algae should be able to respond quickly to increases in nutrients.

Again, I don't know what animals are being fed in this system, but one cube of frozen food per day is sounding like fish starvation in progress.

I have always fed my tanks quite a lot, especially when I used to be using an algal turf scrubber. When I first started using an algal turf scrubber (one with pretty high capacity), I had been having vexing algae problems in the system for many months. Within a week of the right sorts of algae getting established in the ATS, the problem algae were dying off, and shortly afterward the problem was gone. And then I could feed this system with wild abandon.
 
What is the photoperiod for your ATS currently? I used to just run the lights at night on mine.
 
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