MH vs PCs

[stilmas]

right on Mariner,
Do it right the first time, and like I said before, if I could afford it I'd go to MH also. I very well might do so when I upgrade tanks and get a damn raise at my job!! But in the meantime it looks like PC and VHO are in the works for me.

[ November 15, 2001: Message edited by: stilmas ]</p>

 

[mariner]

Your electric bill is still measured in watts!!!!!! The amps have nothing to do with costs!!!!!!!Amps are only a way of calculating whether or not a circut breaker can handle the load or not. 1000 watts of flouro on an electronic ballast are the same as a MH on an electronic ballast. Add up all of the amps to make up 1000 watts of flouro and you'll see that its the same as the MH. A MH tar type ballast will use a little more energy because it watstes some of the electricity by turning it into heat. But, like I said, the price difference in buying an electronic ballast instead of a tar ballast is like 100-200 bucks. You might save a few dollars a month on your electricity costs. At that rate, it'll take some years to get your cost difference back. I'd rather just buy the tar ballast and have the versatility. You know, an electronic ballast will not run all bulbs efficiently.
Some bulbs are not run as bright on the E-ballast where on the tar ballast they would be better. Look at this years issue of Marine Fish and Reef USA. There is an excellent arcticle on this whole issue.

[ November 15, 2001: Message edited by: mariner ]</p>

 

[npaden]

sMARTY,

There is plenty of data out there that will provide you support for the data you are looking for. I used to have several sites bookmarked on my old PC but didn't bring them forward to the new machine.

Basically there is not a lot of difference in lumens per watt provided from any of the major high intensity lighting types. Actually I believe MV lighting has a slight edge over PC then followed by MH and lastly VHO. All of them fall within around a 10% difference though if you are using the same spectrum of lighting.

The area that can actually provide the largest variances in output is the color temperature or spectrum that the bulb is running at. A 20K MH bulb will output significantly less lumens than a 4300K bulb. Same with a cool white flourescent vs an actinic.

Efficiency is very similar in the major high intensity lighting choices as well. All have heat loss with the ballast except possibly the electronic VHO ballasts and they are actually a little more efficient that the other choices. They also have the lowest lumens/watt output so you basically have a break even there.

As far as price - the MH or MV are by far the cheapest option. I've yet to drive by a car lot or a warehouse store that used power compacts for their lighting source. When it comes down to it MH is by far a cheaper alternative in both up front costs as well as continuing maintence including bulb replacement and energy consumption.

As far as spectrum shift being more dramatic on MH than PC or VHO I've actually thought that was the reverse but I'm sure it has a lot more to do with the spectrum you are using than it has to do with the type of setup. I bet a 20k MH would shift faster than a daylight VHO or PC, but a 6500K Iwasaki would shift slower than a VHO or PC actinic bulb.

Oh well, there is a lot to cover on lighting, but one thing that is a fact is that MH is the cheapest setup by far unless you are dealing with a fairly small tank.

FWIW, Nathan

 

[bigtank]

I agree with Nathan. I also think that HQI is the best and brightest (PAR/watts consumed) type of metal halide suitable for aquarium use. Imagine a small double ended bulb, only 150 watts, that whips 175w mogul base bulbs and is brighter than most 250w mogul bulbs. On top of that, the color is nice and you can keep anything with them. I use 2 150w 10k and love 'em. These bulbs are actually too bright for some animals IMO, but they also come in 70w. Or, for a dedicated SPS/clam tank, you can get 250w HQI.

 

[pez]

Look, 400 watts of ANY lighting is 400 watts of electricity. The whole argument that PC uses less electricity than MH is total crap. HOWEVER, you can get electronic ballasts for PC and VHO lamps. Electronic ballasts are more (some times much, much more) efficient than tar (can and coil) ballasts.
In the real world, any lighting choice using an electronic ballast will generally use less electricity (and cost less) than a standard ballast. So anyone who says PCs use less electricity than MHs have to present the facts first. Anyone who believes you can get 400 watts of light from 300 watts of electricity surely also believed in the easter bunny. There are laws of physics you just can't step around, despite the greatest of advertising and marketing.

-Tom

-Tom

 

[redneck]

The electric cost arguement, that PC/VHO uses less power than MH rated for the same watts is true. On a practical sense, this is especially true for the electronic ballasts, which light the flourescent lamps differently than a tar ballasts and often draw less than the rated bulb wattage and produce more light (than a tar ballast). The Metal halide e-ballasts haven't proved as effective. The tar ballasts for MH, and the CAP & coil aren't as efficient, and more power is drawn than the rated wattage.

Yet the arguement that running PC/VHO is cheaper than MH is crap. Once bulb replacement costs are factored in, the difference in electric use is laughable. (The only exception might be the poor saps in california. There it might be an even trade.) Compare bulb replacement costs for 4 110W VHOs vs 2 250 Iwasakis. In 18 months, you need to replace the VHOs three times (4X30$X3 = $360) the two Iwasakis are just nearing their replacement time. (2x$60=$120). PCs and VHOs are cheaper to aquire, and more expensive to run. The e-ballast payback for MH isn't good either. Ever see the payoff period calculations Sanjay Joshi did on MH e-ballasts? In CA electric rates, it took 7 years to pay off the difference in ballast costs.

The actinic arguement on MH is crap too. They're not required, just preferred by many.

Face it, in general, MH supports higher light levels throughout the tank. Two 250W Iwasakis will smoke 6 110W VHOs on a 4x2x2 tank. (500 vs 660)

The advantage to VHO/PCs is easier light acclimation, and better distribution.

Stilmas, you sound like you're trying to desperately fight off cognate dissonance. And you have reason too!

Smarty, the spectrum shift on PCs/VHOs is MUCH greater than, say Iwasakis. Surf the Aquarium Frontiers archives. They have tests to prove it. As I remember, a two year old Iwasaki has more of it's initial spectrum than a six-month old PC/VHO (even on Icecaps). Flourescent lights loose 10% of their initial intensity in the first 100 hours!

[ November 17, 2001: Message edited by: Redneck Cowboy ]</p>

 

[esmithiii]

Mariner: Watt for watt, PCs put out more light than VHO. They are a newer design than VHO, and are more intense watt for watt. That is why they are more expensive. (or rather why they are popular even though they are more expensive.)

Where is Sanjay when you need him? Or Galleon for that matter?

E

 

[esmithiii]

I forgot to add that the standard "you need MH lighting" is true IMO for just about any tank that is planning on showcasing clams or SPS, and for any LPS tank >20" deep.

 

[mariner]

I have to agree with Pez on the bottom of page 1. It's just plain common sense. Thanks Pez for reaffirming that.

[ November 18, 2001: Message edited by: mariner ]</p>

 

[Iron]

You mean there really isn't an easter Bunny?

 

[SPC]

And no Tooth Fairy?

Steve

 

[esmithiii]

If there's no Santa, I don't want to know about it.

E

 

[StirCrazy]

Pez, sorry to say this but you are way out to lunch.. and befor you confuse more people I think you should understand what is happening in the relation between PC porwe consumption and MH power consumption. when you say 400 watt MH bulb that is a measurment of the output of the bulb it actualy takes a lot more power to creat that.. remember it isn't a perfect world and we don't get out what we put in.. a lot of power is lost to heat. this is whare effiency comes to play.

what I mean by this is a MH system might be rated at say 65% effiency so to get 400 watts of light output you have to put in 615 watt. so you are losing 215 watts of power to heat.
A power compact floresent is one of the most efficient light you can get ( aside from LED but we won't get into them

) so lets say that your PC is 88% efficient.. for 400 watts ( if they made a 400 watt bulb) you would only need to input 454 watts so you are only losing 54 watts to heat for the same wattage out put. so you can see why is so much more to run a MH light that is the same wattage as PC's .

Now having said that the way the light is used is different.. in a PC (we will pick a 36" 96 watt bulb) that 96 watts is spread ofver the entire surface area equaly. that mean the same amout of light is projected from anypoint of the bulb (with in reason.. of course there are going tobe slight variations) now if you take a MH bulb (lets say a 100 watt bulb) it is a semi directional bulb so more light is given off in one direction that another also instead of the total light being spread out over a 36" length it is concentrated to a 1" element ( or smaller) which creates a more intence litght sorce. so now if they are mounted properly the light you might actualy get into your tank off a PC is about 65% of its output (if you are using a real good reflector) whare as with a MH you can probably get over 85% of the light into your tank with a good reflector, and sence it is a more directed light it will penatrate deeper than the difused light from a PC would.

I hope this clears some stuff up.. the main point is that we are not creating power as sugested by Pez but losing it in the form of heat.

StirCrazy

 

[SPC]

And that my friends is why a metal halide in your room is hotter (room temp wise) than VHO or PC.
Steve

 

[Iron]

you can search # on pc and vho they are close enough to call them equal but the price of pc out ways the cost of vho imo unless you use an IC ballast but the pc hoods are way overpriced imo. I agree MH is cheaper in the long run if you want alot of light.

 

[npaden]

StirCrazy,

You are a bit off in your estimation of the efficiency loss on a MH Cap & Coil ballast. My 400W ballasts use 4.0 amps of electricity on a 115V circuit. That is 460 Watts.

I think you will actually have more loss on a PC ballast (unless you go electronic) because to get the 400W of light you will need a minimum of 4 - 96W ballasts.

Either way the difference between actual light output vs. power consumption is + or - less than 15% on all of the standard alternatives. MH is cheapest because of bulb replacement if you go with Iwasaki's.

One good point was mentioned that the double ended HQI bulbs are about the best option even though they are amoung the most expensive up front because of the fact that you probably won't end up using actinics with them.

The problem is that they don't come in 400W so it would take a bunch of them to light a big tank. This is also the problem with PC's. To provide the light I currently have with my MH/VHO combination I would need 25 96W PC bulbs over my tank! At $30 each to replace it would cost me $750 to replace the bulbs on an annual basis. For my MH/VHO combo it costs me $366 to replace all the bulbs but hopefully burning Iwasaki's and using an Icecap setup I will get 18 months out of them instead of 12. Still I'm saving $384 in bulb replacement cost a year minimum.

FWIW, Nathan

 

[Iron]

.

[ November 19, 2001: Message edited by: Iron ]</p>

 

[whirley]

I think the real savings in MH is the replacement bulbs....MH's ROCK! There's no way your going to get that kind of intense light from PC's.

MH's are cheaper and more economical in the long run....whether it would be replacement bulbs or the better output in light.

Sides, I'd get sick of replacing my PC bulbs every 6-8 months....

Just that simple.

whirley

 

[esmithiii]

I like PCs but they aren't really all that compact! To get 1000W (which I have on my 180G) I would need 10 x 96W bulbs, which would be pretty wide, wider than my 24" wide tank.

I love my MH too, though, and wish I had started with it.

E

 

[sawcjack00]

Four words...

You need metal halide!