Metal Halide without Actinic

[Biggen]

Ok, so summer is winding down and now I am beginning to get back to building my reef tank for the store.

I have a quick question though. I will be using a 40 tall (much like my FW setup) as a reef tank. I know I know, tall tanks aren't really the best but that is what I have currently have. Since my tank is 24 inches tall, I have been looking at metal halides for lighting the tank. I was thinking that one 250w MH pendant would be enough light. That equates to over 5 wpg. My question is, if I use a 10K MH, do I still need Actinic or can I get away with the one light?

I guess my question really depends on what corals I want to keep. Right now, that is uncertain. I will probably never have any kind of animal that specifically needs a TON of light. I guess I will just have the "average" corals in the tank that don't require specific needs.

 

[d9hp]

I would go with a 250 watt 20k bulb, that bulb really has a great blue twinkle to it

 

[Biggen]

I would go with a 250 watt 20k bulb, that bulb really has a great blue twinkle to it

Yeah I was looking at the 20K bulbs from hellolights.com. There is only a $6 difference between the two bulbs.

Still, though, $100 bucks a bulb seems like a total rip-off. I am going to check around with some of my local lighting suppliers and see if they can get these bulbs any cheaper. Of course, Coralife probably made their light so only a Coralife bulb will fit into the socket.

 

[d9hp]

Well, most MH bulbs are gonna cost that much, if they are a good one. I know its tough, but you will most likely have to cough up the dough.

 

[Biggen]

Actually I have done some checking around, an most "house" type MH bulbs are around $20 or so. But I bet their spectral output is around 5K or less...

 

[shawmutt]

How can home depot have them for less than $20? Are there different spectrums like in flourescent?

 

[reefrunner69]

Yes the higher spectrum bulbs are made specifically for aquariums and cost a premium. FWIW, the bulb replacement cost will be close to the same as if you lit with VHOs.

Are you using one of the CoraLife bell pendants?

 

[reefrunner69]

BTW, you might look into the Iwasaki 6700K and supplament with some PC true actinics, may be able to get into the Iwasakis for cheap enough to pay for the actinics, also if looking at 20K bulbs, look into the radiums, IMO, coralife MH bulbs suck. I am using a Ushio 10K MH and when brand new, it was fine without actinics, after about 2-3 months burn time, I really prefer it with actinics. I've heard the Hamilton 10Ks look good without actinic supplamentation, as well.

 

[Biggen]

Are you using one of the CoraLife bell pendants

Yes I was looking at getting the 250w version. Although on the hellolight.com website it says, "175W Pendants have an acrylic shield, but 250W and 400W do NOT have them." Are they talking about the shield that goes on the bottom of the pendant that blocks out UV light? I will definitely need that... I wonder if they are referring to something else.

I am trying to go with just one bulb type in order to keep cost, space, and heat down to a minimum. What about the XM bulb? They claim it will produce 20K after 100 hour burn in time. Any thoughts about it?

After looking into the Radiums, I noticed they don't work well with M58 ballast's which is what I assume the Coralife Pendant is working off of. Can anyone confirm this? Perhaps I read it wrong...

The Ushio's do look good but I don't want them to shift spectral output in just two months time. Have you had many of these bulbs before and, if so, have they all done this.

Haven't found any Hamilton MH. Will do a search on those now...

 

[reefrunner69]

All bulbs will shift spectral output in a couple months time, that is the burn in. My Ushio has not shifted any noticable degree in the last 6-7 months.

I don't recommend the bell pendants, MH are more efficient (as well as their reflectors) is mounted horizontally, rather than vertically.

No idea on the XM bulb, but if it is one of the cheaper bulbs...do a search on my experience with Vion bulbs. I would imagine it is the same difference.

If you are still in the planning stage...keep your options open

 

[Biggen]

You know what?? I just remembered I have a center brace on that Acrylic aquarium...

I wonder if 250W would melt it.

[sigh]

 

[reefrunner69]

I doubt it, but it would certainly cast a shadow.