MH vs PCs

[sMARTY]

Can we all please stop giving the standard "You Need MH" answer every time someone asks about lighting. Seems to me that intensity and spectrum are the important factors. If you set up two identical systems side by side, one with MH and one with PCs (or VHO for that matter) as long as intensity and spectrum were the same, I don't think that your corals or clams would give a $#!^. I would love to see some documentation showing which is more efficient (Lumens/Watt). If one type were substantially more efficient than the other, I could see an advantage. By the way, don't MH bulbs have a significant spectrum shift over the life of the bulb? If so, I would give the edge, in spectrum at least, to PCs. I understand that everyone has their own preferences, and that different situations call for different solutions, but MHs are NOT the only correct solution.

 

[MIKE NY1]

sSmarty, I run only PCs basically because of the heat factor. I don't want to get into chillers and fans etc..Anyway if we take your scenerio of two identical systems with the same intensity and spectrum, one being MH and the other being PCs I think the MH system would be more benificial for light demading SPS and clams because MH gives point source illumination which provides glitter lines which strike deep into the zooxanthellae of the animals.

Just my opinion
Mike

Remember our American heros...NYPD,FDNY,PAPD

 

[Bubafat]

Ya, lets see you try to get the same intesity of MH with PC's...Good luck!!

Buba

 

[Ben1]

I run PC's on my Soft coral tank and MH on my SPS tank. I would not try to do an all SPS/clam tank with PC's, which also have a spectrum shift over their life. You may be able to grow SOME sps with PC's but only close under the bulbs. I love my PC's for my Softie tank though.

 

[mariner]

PC's will get just as hot as MH. Try eight 55 watt PC's which will give you 440 watts and then try a 400 watt MH. I'll bet the heat factor is very close. Besides, When you put a cheap clip on fan from walmart on the MH bulbs, the heat is greatly lessened.

 

[micagreenmachine]

PCs do give off a lot of heat. I haven't been really happy with them, but they've been getting better now that they've come out with new bulbs with better K values. I've got 4x96 watts on my tank (2 10K, 2 actinic) and it heats up pretty well in when the lights are on. Just got the 2 new 10K bulbs for it and it looks much better. Chiller required to keep temp stable. I'll be switching to MH when I move to a new tank. 2 10K PCs are going to go for fresh water planted aquarium. Other 2 may join the MH hood to give a little more actinic.

Besides, MH just plain old looks better IMHO.

~t

 

[stilmas]

What about the electricity draw that is significantly higher with MH. You can't say it's not!!

 

[sandmanrieast]

What about the electricity draw that is significantly higher with MH. You can't say it's not!!

Some things in life are just worth it.........
do you think marine land and other Aquariums across the land use Pc,s ....we must fight going the cheap way out sometimes....

 

[stilmas]

is anyone in the hobby as financially secure as those large attractions?

 

[pez]

400 watts of electricity is the same whether it is PC or MH. So MH use no more electricity than PCs (ignoring any ballast loss, which can be substainial for tar ballasts).

The real argument should be how much light do you get for those watts. If I remember properly, 400 watt MH edge out PCs and all other FL lamps on a watt/PAR basis. I don't think the same is true for 175 and 250 watt MH lamps though.

-Tom

 

[stilmas]

dude,
the 400w is the wattage that the bulb burns at, NOT what it is drawing from the wall. The amount of AMPS that it is drawing from the wall is higher in MH than PC or flourecent = more electricity drawn.

 

[stilmas]

Also, if you can get your hands on one try this, I did..Get a 1000w MH and fire that puppy up, go outside and watch your meter just about spin off your house. Now fire up 1000w of flourecents and watch the meter spin much slower. All of this really doesn't mean much because to be in the reef hobby you have to have alot of money to begin with so $20+ more a month is no big deal, but for someone on a budget this stuff may come into play.

 

[mariner]

I agree. PC's don't give the ripple effect like metal halides do. Also, consider the cost to replace the amount of pc bulbs to give you the same wattage of a metal halide.

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

 

[sMARTY]

You guys are making my point for me. The reason very few accurate comparisons are made is that when one looks at MH lighting, say 2x400W 10000K lights, and compares that to a set up of 8x96W PCs (close enough wattage for this example), we often compare the MH without Actinic suppliments to the 8x96W PCs with 2 or 4 bulbs being used for Actinic lighting. Can we at least compare apples to apples?? I think that everyone will agree that comparing 800W of MH to 384W of PC is a little less than fair.

 

[Katspaw]

I can answer this very easily, I run pc's and MH on the same tank. Call me stupid if you want, but I started out with 4 PC 96 watt on my 90 gallon tank. I got them when they first came out. In the beginning you had a choice of 6500k daylights and 7100K actinics, they increased these to 10,000k and the 03 actinics, and I got the new bulbs, I could keep/ not grow SPS corals. At least I didn't kill anything with my lighting, at the beginning of the summer I bit the bullet and bought MH 250 watt 6500k isawski bulbs and a chiller

Now I traded Sue Truett back in April and she gave me a nice orange monti cap with a green rim( about an inch and a half long)from her tank. It pretty much laid there and didn't really show much signs of life. After I added the MH's This coral decided life was good, it is now a fully formed cup shape to it and is about 4 1/2" across from side to side. Now I still have the PC on the tank, including the daylights. I use the actinics for dusk and dawn effects, the daylight kick on about 7:30 as the sun is just getting up and the Mh's kick on about 11:00 just in time for the mid-day sun. And you should see the difference in the light. For some unknown reason I have better results with this set up than with my frag tank that has VHO's and MH's only. So you figure it out. I am happy with the growth I am getting in my show tank and why bother with the frag tank if it doesn't preform like I want it to.

Tracey

 

[stilmas]

True, but the bottom line is watt for watt a MH ballast will draw more current from your wall, and yes is more intense lighting, but that's why it costs more to run. It takes more energy to not only ignite a MH bulb but also to burn it. That's all I was trying to say...Now this is why VHO is less expensive too, like you said, you would have to add either a PC or VHO ballast to a MH lighting system for actinics. That will total you most likely ~$500+ including bulbs with an Ice Cap solution, not including the canopy! You see very nice sps tanks kept with VHO only which would cost about half and cost less to run every month. Most people go with MH cause they have the money not cause it is absolutley necessary.

 

[Super Len]

A reminder that watts = amps x volts. So amps do matter.

I partially agree with sSmarty. Assuming similiar energy input and similiar energy wasted as heat, the light produced should be roughly equalivalent.

However, we must consider one critical issue: MH bulbs occupy less physical space, and distribute light in a more concentrated radiation then a 36" PC bulb, or 48" VHO bulb. This is crucial, because 1. you can only fit X amount of florescent bulbs over a given area and 2. at any point in the immediate range of the MH bulb, the light intensity will be significantly greater (eg more lumens & PAR at any given depths).

This is the only argument for MH that I find has substantial merit.

Utilizing MH allows for more light over any tank, period. However, watt-for-watt, I don't think there's much differentiation. I would love to see a test performed evaluating the lumen and PAR values that each lighting type produces, and compare per watt figures.

[ November 15, 2001: Message edited by: Leonard v2.01b ]</p>

 

[stilmas]

I agree 100% Leonard, that MH will saturate at greater depths and therefore most likely give you more PAR, but somehow this all got turned into how much energy consumption is involved in the two types. If I could afford it, I would like to use MH, but unfortunately I can't and not to mention a $700 chiller to fight heat problems if necessary. NO THANKS!

 

[sMARTY]

Leonard, I couldn't agree more with what you said. And If I were trying to pump as much light as physically possible into my tank I would use MH. However, I would use 1000W MHs not 400W. I don't say this to be a sMarty a$$, only to make the point that most of us are striving to provide an amount of light acceptable to our captive creatures based on our estimates of what they recieve in their natural habitat. As for the radiation pattern for the MH bulbs, this is an excelent point to take into consideration. It has its pros and cons, but could definately be an advantage (or disadvantage), depending on your tank size.

Other than the radiation pattern, and possibly the shimmer lines, I have heard nothing, and seen no evidence to move me from my initial belief.

I find it interesting that no one mentioned the severe spectrum shift over the life of MH bulbs. This is an important issue to people making a lighting decision, and I am surprised that it would be so readily ignored.

 

[mariner]

I'm not trying to be a smart a$$ either. I'm just saying that over time, MH's are cheaper. Like I said(lets use 250 watters as an example), a 250 watt MH bulb will cost roughly 75 bucks. Now to get that many watts out of pc, it cost about 125 bucks(5x55 watters @ about 25 bucks a piece). Pc are great, don't get me wrong, but the larger tank you have the need for metal halide becomes more evident. I would say PC's are at the bottom of the high intensity lighting where VHO are second and MH are first, IMO. Buy what suits you. I'm just offering advise as we all are here. I bought Pc's in the beginning and as I got more into the hobby I ended up with MH. Now if I would have just bought the MH in the beginning, I would have saved a good deal of money. No matter what you buy, you'll always want more. So, IMO just save and get the top and you won't have to upgrade later and waste money.
As far as heat from MH, I have a PFO dual 250 watter setup with the buls about 5 inches away from the water and my tank temp goes up about 2 degrees throughout the day and I only use a clip on fan from K-Mart set on low for any cooling. The only time I think you'd have a heat problem is in the hot summer when no AC is available. Besides, there are temporary remedies for that. Just freeze a water bottle and drop it in your sump.