Question about metal hilides

[EVO]

Hello everyone. I have a question regarding metal hilides I hope someone can answer. I just got a unit with 2 150W 20000k double ended HQIs. When I got the lights the glass lens under one of the bulbs was broken. I am contacing the dealer to have this replaced meanwhile...

I had the lights on for 10 hours, on the side missing the glass lens 2 anemones seems to be a little sunburnt and one coral got toasted. I put the old lights back on for now but does anyone know if there some sort fo UV filter on the glass lens. Does anyone run bare bulb 20000k? Or are these just too strong? I noticed the purple algae on the top of the rocks on that side nad taken on a brown color... does this mean they're dead or just changed color because of the lights?

I hope to get this under control because the LFS guys are always saying you need to have metal hilides for corals. BTW the lighs are suspended about 8" from the top of the water. I've moved the coral to the bottom, I hope it has enough to grow back again.

Ugh... lets vote... should I return these lights and stick with 4x65w compact UVs?

 

[Anonymous]

All normal glass is a UV filter, so it doesn't need to be anything special. Sounds like you are zapping that side of the tank. I would get a pane of glass in there before running the halide any more.

 

[Anonymous]

Dan is right..Since MH's for the most part put out UV-A and not UV-B and C (which would be really harmful to you and your life) a piece of glass will definitely filter out the UV-A..That wouldnt be the concern..I would keep your MH's..If the anemones are bothered by the light, they will move on the other hand you can try raising your lights a few inches and every other week or so slowly lower your lights down until its 8" above the water like you have now..(this can acclimate your critters to the new light)

 

[Anonymous]

Get a piece of glass on there. Besides possibly burning the corals in the tank, you really DO NOT want to accidently splash water on a hot MH bulb as they tend to explode.

 

[EVO]

Thanks for the info guys. I have the UVs back on the tank right now and wont be running this untile they get me a glass lens and timer for the ballast to time the hilides and the actinics seperately. They told me when I asked them that there was a timer on the ballast to set the lights indiviually but when it came it only has switches BASTARDS!

Regarding the amount of light. You guys think 150W MH on each side of a 72G bow front is too much? The UV lighting actually looks brighter but I guess the light is not from a point source and thus less intense.

 

[cjsrch]

if it looks brighter it probobly is jus t amind trick.
iv never seen any thing that isnt point source look brighter then a non point source of same wattage. ( or even close watage)

hope you got 20k bulbs yup you did good job

i for get the fourmula. some one help but you loose alot of light for each ft it is above the tank.

 

[cjsrch]

oh also dont buy one of the coralife timers. they tend to quit. ( youll see what im talking about if you do get one and put a nice load on it)

 

[Anonymous]

Thanks for the info guys. I have the UVs back on the tank right now and wont be running this untile they get me a glass lens and timer for the ballast to time the hilides and the actinics seperately. They told me when I asked them that there was a timer on the ballast to set the lights indiviually but when it came it only has switches BASTARDS!

Regarding the amount of light. You guys think 150W MH on each side of a 72G bow front is too much? The UV lighting actually looks brighter but I guess the light is not from a point source and thus less intense.

:lol: I've got that, plus 2 96w actinics and 3 moonlights on my 72 bow so I think you are fine

 

[ZooKeeper1]

Regarding the amount of light. You guys think 150W MH on each side of a 72G bow front is too much? The UV lighting actually looks brighter but I guess the light is not from a point source and thus less intense.

Not at all 20 k bulbs in general are lacking in intensity. If you are looking to keep light loving organisms in your tank, you'd be better of with 10 to 14 k. Those bulbs put out much more usable light than the 20k's.


i for get the fourmula. some one help but you loose alot of light for each ft it is above the tank.
It's not a formula, it's the inverse square law.

 

[Anonymous]

So I pose a question..I hear burning of corals..But in fact does that really happen..considering in the wild they are exposed to much more intense light then Halides. They dont burn do they? Ive heard (no scientific data to back up) that perhaps their symbiotic zooxantellae are a reason (or atleast one reason) why they wouldnt be susceptible to UV burn...Granted in a tank, they are under intense lighting and in more shallow water. Ive never seen corals "burnt" from the lighting..Can anyone help me understand this better?

 

[ZooKeeper1]

So I pose a question..I hear burning of corals..But in fact does that really happen..considering in the wild they are exposed to much more intense light then Halides. They dont burn do they? Ive heard (no scientific data to back up) that perhaps their symbiotic zooxantellae are a reason (or atleast one reason) why they wouldnt be susceptible to UV burn...Granted in a tank, they are under intense lighting and in more shallow water. Ive never seen corals "burnt" from the lighting..Can anyone help me understand this better?

I believe the jury is still out on the lighting issue. Do to alot of different factors including cloud cover, angle of the sun, water clarity and a few others, some of us might be providing too much light to out corals. A few noted hobiest are running a 2 hour halide cycle a day, their claim is that the intense lighting will quickly excite the zoox. (like the blast for the few hours around noon) and they will stay excited and photosynthesize long after. Of course they still use supplimental lighting the rest of the day.
As far as corals burning, I doubt a healthy coral would, there are plenty of reefs that are exposed to direct sun for hours during low tide, they do fine. The problem may be improper acclimation to the new lighting. Take a coral that is used to pc's, and put it under halides, and it may burn. Take a coral that has bleached, even slightly, and put it under more intense lighting, and it may burn. I believe the pigments in the coral itself play a role as a sunscreen by reflecting light. Since alot of corals lighten up in our tanks, they might be more succeptable to burning when already stressed by other factors.

 

[EVO]

Okay, so the coral is coming back now... I'm willing to give this another try with the hilides. So... after I get the glass lens replaced and get the thing on a timer...

* How many hours a day to run the hilides?
* Is it okay to only have actinic blue for the rest of the time?

Thanks for all your suggestions.

 

[ZooKeeper1]

Your gonna want to start with just a few hours a day, and slowly increase the length they are on about 1/2 hour at a time every 5-7 days. Actinics are fine for the rest of the time. I run my main halide 6 hrs a day, the rest of the day, I have a 20k on.

 

[cjsrch]

hey! i just went to fmas and they had someone talking about MH lighting and how to make the best of it.

all 400 wat lights are not the same and the same bulb on diff ballast may put out more or less light!.

now . halied do drop in intensity alot over the course of 2 years. and if you have a small canopy ( like i do) the bulb will need to be change often so that the coral dosnt get used to lower intensity followed by nuked by new bulb.

and there are no real 20 k bulbs ( some of these bulbs are actualy almost useless ( usio i think was one of them) it only put out in blue...)
20 k can mean many diff things. id recomend going to this guys site. ( ill get it for you later as i forgot the url)

but you can make MH (and florecant lights) last longer by buying more powerful bulbs and having them higher off the water ( 18 inch or more) and then slowly lowering them throu out there life to maintain a constant output.


also many reflectors are almosted worthless if put to close above the water ( spyder was teh worset for under 6 inch) it had only 2 strong intensity area that were about 3 inches big altho when it waws raised it had a bigger area but weaker output over that entirearea

 

[ZooKeeper1]

Thanks to Sanjay Joshi, and a few others, it is easy to check the spectral output of these bulbs. 20k bulbs absolutely put out more than blue wavelenghts, they just have large spikes in the blue. Saying there is no such thing as 20k light is wrong also, it's just that the companys dont necessarily put the correct k rating on the box. This is true for all bulbs, not just 20k's

 

[SnowManSnow]

While we're vaguely on the subject. I just installed a 14k Blueline DE MH in my pendant.. and IMO its just right looking

 

[Anonymous]

My understanding is that DE Bulbs do not have the protective glass envelopes that SE bulbs have. LENSES ARE REQUIRED FOR DE BULBS!! You will burn your corals and your eyes without one! There is no shield for the UV radiation produced by the bulb. I can't take time to look up the references right now as I am at work, but do yourself and your tank a flavor and do not turn on the light without the glass shield in place. I'll edit this post later with references if I can remember that long.

 

[zack136]

cknowlto, You are correct. You need a u.v. shield for a D.E. bulb

 

[cjsrch]

your 2ok may not be real 20. there are some( most) mh bulbs that claim to be 20 k but are SOOOOO FAR OFF ill get you a web site that tell you all the stuff ( guy has over 101 different bulbs and ran them on dif ballast and tooks 580 or so test)

 

[cjsrch]

Thanks to Sanjay Joshi, and a few others, it is easy to check the spectral output of these bulbs. 20k bulbs absolutely put out more than blue wavelenghts, they just have large spikes in the blue. Saying there is no such thing as 20k light is wrong also, it's just that the companys dont necessarily put the correct k rating on the box. This is true for all bulbs, not just 20k's

yup hats the guy. there are NO TRUE 20 k bulbs according to him. ( he was at the fmas thing yesterday. he says ok after every sentance lol)