CFL Lights compared to MH

[GreenMan13]

So I have a few fresh water tanks currently but I want to do a reef tank come the middle to end of the year. I plan on doing a tank size of about 55 gallons or so. My question is on lighting.

It seems that most people would suggest about a 250 watt MH for a 55 gal. tank right? And it seems that luminous flux is more of what matters then watts since how much light the bulb gives off rather then the energy the bulb uses.

So I looked into how much lumens a 250 watt MH bulb gives off. I looked up the values for Ushio 250 watt and found that it gives off 11000 lumens.

So I went on a search to find out how many CFLs it would take to get 11000 lumens. The CFLs I'm talking about are not the long tubed ones but the short screw into a normal socket one. I came up with GE 26 watt Daylight CFLs. They give off a mean lumens of 1325 lumens. With 8, this would give a total of 10600 lumens.

The other thing I have seemed to notice is most people go with 10000K color temperature which the MH have. The next most common according to the poll on this site is 6500K. This is the color temperature of the GE Daylight bulbs.

IMO Pros: 8 26 watt bulbs will use only 208 watts compared to 250 watts
Will not need a ballast which will make it cheaper.
Bulbs said to last just as long as each other.
Bulbs will only cost $40 instead of $60+
Can turn off portions of total light to simulate sunrise and sunset?

Cons: 6500K will be a little less blue then 10000K
Others???

In adition to the CFLs I would plan to use some actinic lighting also. What I want to know is what kinda problems might I have with this type of lighting?


Thanks for all the info this site has already given me.

 

[cindre2000]

16 screw in compacts? With additional actinic lighting? Do it if you want; however, I don't know what kind of results you will have. You will probably have trouble with light needy corals but be fine with softies and maybe some LPS...

If you have the money you could experiment, place a 250w metal halide on one side of the tank and the 8 PC on the other and see which has more light.

I would personally say that you should go with two 150 or 175w metal halide with iwasaki bulbs (for long life), and then add in your actinics. However, if you plan on upgrading, the 150/175 would not necessarily be in your best interests since they would limit your tank options for maximum growth due to the depth of penetration. However, if you got nice reflectors when you upgraded you could probably pull off using the lower wattage bulbs; which is what I plan on doing.

 

[GreenMan13]

So for a 55 gal, two 150-175 watt MH would be good? If I was to only use the lumens from 150-175 watt MH, I would only need 6 CFL on each side totaling 12 bulbs. This would actually give more lumens from the CFLs then the MHs.

This would not be as fun wiring as a two MH kit would but it is not a problem, only a little extra wire. I am still researching trying to find higher watt CFLs, but they are only starting to be made so they are not as cost effective right now. This may change a lot considering how much CFLs have changed in price just over the past couple years.

And you mean I would want to use 2-250 watts if I was going to upgrade to a larger tank later right? This would also allow me to upgrade in the future if i was to go to a larger tank just by adding more bulbs.

Thanks for the input. More comments are always welcome.

 

[mr_X]

i really want you to try this experiment.
please take lots of pics as well. :wink:

another reason people choose metal halide is that it makes the tank look beautiful. the shimmer you get from those lamps above your tank is really something. after all, the second most important thing, besides promoting coral growth, is having a tank that's visually pleasing. something you can sit and watch for a while. i think halide covered tanks are the best for this purpose.
good luck!

 

[cindre2000]

The issue between 150/175w metal halide and 250w is that 250w bulbs will work fine for a lot of higher light corals in a deeper tank. Since most larger tanks get fairly deep, 24-30", 250w is usually a 'standard' choice.

150/175w lamps would work fine shallower tanks, and they can work well in deeper tanks if you position your coral carefully and use really good reflectors. However, most people feel it is easier to put in a really high wattage bulb and be done with it.

Either way, one of the main benefits of a metal halide is that they are one of the easiest pieces of equipment to 'bring with you' on an upgrade.

But it would be cool to see the difference in light output between PC and MH. Mr. X is definitely one to talk, you should see his first tank, and his current tank!

 

[GreenMan13]

So far it sounds like this will work. Reading Feature Article: Lighting the Reef Aquarium - Spectrum or Intensity? helps me feel reassured about not killing the coral.

i really want you to try this experiment.
please take lots of pics as well. :wink:

I will definitly take lots of pictures. I'm really into photos and I love seeing how things come together. I have looked through your whole thread about your 200 gal. The pictures make it so much better. That is actually why I used the Ushio for the lumens of a MH since it was fresh in my head from reading about your tank.

150/175w lamps would work fine shallower tanks, and they can work well in deeper tanks if you position your coral carefully and use really good reflectors. However, most people feel it is easier to put in a really high wattage bulb and be done with it.

I'm thinking about maybe doing a DIY reflector...maybe out of mirrors...that is really just a very initial thought though. I will not be doing this until about Aug. since I will be moving then and I think it would be bad to start a reef tank now and get it going smooth just to then have the hassle of moving it. Waiting also gives me time to figure out all the details and build anything that i need to.

 

[cindre2000]

Feflective aluminum is a lot better than mirror, especially since it is lighter and easier to work with. However, white works almost as well as reflective aluminum.

 

[IslandCrow]

Realize that it's not all about lumens. Actually, it's not about lumens at all. It's about PAR. Don't ask me what PAR stands for, I can't remember at the moment, but basically, it's the amount of light that can actually be used for photosynthesis. The next thing you need to worry about is the ability of the light to penetrate to the depth you need. MH concentrate their energy very well and have great penetration capability. Of course, as has been mentioned, with a shallow tank, this is not as big a factor. I don't think you'll be able to get the PAR you want for light demanding corals even if you do match the lumens over the total area of the tank. I think your plan could very well work for less light demanding corals, though. I've used a single 26W CF bulb for my in-sump refugium and successfully grew mushrooms and xenia, so 8 of them could certainly do the trick as long as you're happy with the color the light puts out. Just make sure your setup is protected against salt spray and water splash, because you're going to have it. Water splashing on a normal screw-in socket is obviously an electrical hazzard. The salt spray will of course corrode the metal very quickly.