Mercury Vapor

[ShaneDolan]

Does anyone here have any experience with mercury vapor lights(High Pressure) I really like the colors they give I have used them in different applications in the past, Just curious if they would work for saltwater? I have 2 laying around that I am not using right now.

[David Grigor]

The only Mercury Vapor bulbs that I'm aware of that are suitable for reeftank is the Iwasaki 6500K bulbs. Very yellow looking but man do the corals grow like wildfire under the 250w - 400w versions. The don't make a 175w version.

They were very popular 8-10years ago, but now so many people prefer blue bulbs they don't get much attention now days.

[ShaneDolan]

I used them to grow tropical plants for a while and there 400w I cant use them on my 20L but I have plans big plans.:cool:

[ShaneDolan]

The only Mercury Vapor bulbs that I'm aware of that are suitable for reeftank is the Iwasaki 6500K bulbs. Very yellow looking but man do the corals grow like wildfire under the 250w - 400w versions.


Do they have a phosphor coating to make them yellow, Mine always had a blueish green color and they were clear,but I do know they make some bulbs with a coating inside to change colors or color correcting as they say. The standard mercury vapor lights are yellow too I believe.

[David Grigor]

No coating, because it's a 6500K rated bulb it's pretty yellow by todays bulb standards. Even 10K is considered yellow to most now. Years ago, there were talks about trying to alter the color using filters but that reduces the useful ness of the PAR that make the Iwasaki go great. If you need a bulb to grow coral fast without care to the coloration, Iwasaki 6500K bulbs are the bomb. Trouble is nobody really wants a BIG brown coral.

A standard mercury vapor may produce ( don't really know much about them ) much of it output in spectrum that isn't really valuable to PAR readings. By the time you account for this, the output vs. watt used may make them terribly inefficeint for our purposes. I know this is the case with Halgen bulbs.

I assume this is the case, or they would get more attention in our hobby. Especially years ago when MH bulbs options were so little, if this was a viable option it would have definately been talked about.

[ShaneDolan]

Maybe I will stick to plant growing with them. hmmmm.....thought process continues.

[scubaspew]

Maybe I will stick to plant growing with them. hmmmm.....thought process continues.

Shane if you have a 400 watt one laying around I'd be willing to do a little test, short term I don't think it could hurt much and I'm curious. I'm going to see what I can find out about them.

[David Grigor]

Oh it will work no doubt, it's just that for the amount of usable light per watt used will likely be very ineffecient.

[ShaneDolan]

your corals will live but look not so good. I might just pull them out of storage they have huge reflectors for plants on them so they may need new ones Ill see what the deal is.

[mattb]

Mecury Vapor lamps don't have much in the way of blue/violet spectra in them. The spectrum is all red-yellow-green, which is good for plants, not zooxanthellae.

[scubaspew]

I guess I am just curious, what about alternating bulbs for growth and color? Or would this just cause undo stress?

[ShaneDolan]

I know I can grow some amazing bromiliads, and orchids with it.

[mattb]

I guess I am just curious, what about alternating bulbs for growth and color? Or would this just cause undo stress?

why would you need two different bulbs to accomplish this? There are lots of really good bulbs that are good for both..... You can get good coloration with Iwasaki 6500K and crazy growth, but you'll need to add some good blue T5s or VHO to offset this..... Coloration is fair from a simple light bulb decision, if your corals aren't happy, they wont be particularly colorful. There is a 'cost' to produce pigments.

[scubaspew]

why would you need two different bulbs to accomplish this? There are lots of really good bulbs that are good for both..... You can get good coloration with Iwasaki 6500K and crazy growth, but you'll need to add some good blue T5s or VHO to offset this..... Coloration is fair from a simple light bulb decision, if your corals aren't happy, they wont be particularly colorful. There is a 'cost' to produce pigments.
Matt, I guess I was just curious. I run a 400 watt halide and a 20,000k radium bulb. I love the look of my tank but at the current time have no way to add t5's. I would love to increase my growth and not lose my color. I am assuming by what you are saying that an Iwasaki 6500k would not be a good choice on it's own? Just curious about other bulbs that's all.

[mattb]

You'll get good growth with the Radium... in due time, patience grasshopper.

Back in the day, I did, but that was the 'whitest' bulb then....

[scubaspew]

You'll get good growth with the Radium... in due time, patience grasshopper.

Back in the day, I did, but that was the 'whitest' bulb then....

Thanks for the advice Matt, I appreciate it!

[David Grigor]

Here's a real life story for comparison, obviously there's more to growth than just bulbs but story interesting to give you an idea.....

Back in 1999-2000ish range, Agu ( now lives in FL ) ran 400W Iwasaki, I ran 400W 10K Ushio. Actually my reflectors where better his was just a Hamilton fixture with just white inside compared to my spiderlights.


Anyways, I had a colony about 6" or so in size of what I believe to be a Acropora micropthalama. Nothing really special and quite common. Well I gave him a frag. Next time I saw him which was about 18months later at a meeting he was hosting, the frag I gave him actually outgrew and was larger than my whole colony which had a good 6"+ head start. By that time mine was about soccer ball sized while his was basketball size. As far as looks mine was a bit greener looking but really that coral isn't much to look at regardless.

To give you an idea, what type of growth your talking about using a 400W 6500K Iwasaki. Incredable but you definately sacrifice looks.

I ran 400W for about 6 years or so, the last 4 years being the 400W 20K Radium and hands down was my favorite best of both worlds really corals looked nice and pretty nice growth. This was running on HQI ballasts and was a nice color.

[scubaspew]

Here's a real life story for comparison, obviously there's more to growth than just bulbs but story interesting to give you an idea.....

Back in 1999-2000ish range, Agu ( now lives in FL ) ran 400W Iwasaki, I ran 400W 10K Ushio. Actually my reflectors where better his was just a Hamilton fixture with just white inside compared to my spiderlights.


Anyways, I had a colony about 6" or so in size of what I believe to be a Acropora micropthalama. Nothing really special and quite common. Well I gave him a frag. Next time I saw him which was about 18months later at a meeting he was hosting, the frag I gave him actually outgrew and was larger than my whole colony which had a good 6"+ head start. By that time mine was about soccer ball sized while his was basketball size. As far as looks mine was a bit greener looking but really that coral isn't much to look at regardless.

To give you an idea, what type of growth your talking about using a 400W 6500K Iwasaki. Incredable but you definately sacrifice looks.

I ran 400W for about 6 years or so, the last 4 years being the 400W 20K Radium and hands down was my favorite best of both worlds really corals looked nice and pretty nice growth. This was running on HQI ballasts and was a nice color.

Thanks so much David! I guess I have always been curious as to other options and after hearing that story and doing some research on my own I feel I probably do have the best I can have outside of having an atinic supplement which I do wish I had. I don't suppose they have come out with any kind of smaller clip on atinics or anything else that could easily be retrofitted to a tank like mine? I keep looking and hoping that I could come up with an interesting and cool solution for that. Thanks for the story and the info guys. Shane, I want to hear about these big plans! Tomorrow?

[David Grigor]

Tank like yours is traditionally a frag tank where supplemental actinics aren't used. No clip-ons or anything you would have to design a canopy, light box , light rail to fit them on.


Graham used 2X250W Iwasakis for a long time and tank was pretty nice but to compensate for the yellow he had 4 VHO actinics. This was with 250w, 400w would be even harder to compensate. Likely though like most others back in the day, once your eyes adjust you get used to it and don't necessary see it as yellow as visitors do. I'd for sure stick with what you have though.

[scubaspew]

Well I am going to stick with the 20,000k Radium for sure I like the color. I just want to be able to see my tank at night and with the way my light is mounted vho isn't really an option, I wish it was. Just to have some atinic or some really good penetrating moonlight option or something.

Shane sorry for hijacking your thread. Can't wait to hear more about your awesome idea!

[Zekester]

I know I can grow some amazing bromiliads, and orchids with it.

Do you have any lights you would part with. My parents are looking for some for their grow opperations

[ShaneDolan]

Right now I am holding on too them, might start orchids again. But I will let you know if I decide to sell them.