Metal Halides vs CF vs...

[holry7778]

So I have decided to stop “armchairing” the reef aquarium world. I have read countless books on the subject and am finally starting up a 55gal with a 20gal sump. With most of the equipment covered, I trying to move on to the Lighting…

Honestly I was blown by the astronomical prices that CF lighting hood was going to cost…So I figure, I’d do my research and see if I can build a DIY lighting hood. I would like to keep (in the long-term) an assortment of SPS and LPS corals, maybe 1 or 2 clams, a few fish and the appropriate clean up crews.

So when it comes to picking out lighting I get confused. I love CF-the discharge a lot of light, have an extremely low heat discharge, and last a good long time. However I have read in several places that MH are the way to go since their discharge is so intense.

Will 4x95w CF (2x10,000k and 2x actinic bulbs) work fine?

Or should I plan on having two 175w MH (65ook, 20,000k) with a couple of actinic fluorescents bulbs on the sides?

 

[ChrisRD]

Hi and :welcome:

IMO, considering what you want to have for future livestock it's no contest - go MH.

CF lamps need to be changed out yearly or sooner. Most MH lamps will go a year (some more, some less) so IMO there's no lamp life advantage with CF.

There's no comparison as to the difference in intensity levels - MH is far better.

As for the heat thing - MH lighting systems are more efficient, so if it's generating a little more heat, it's delivering a LOT more light to your corals than the CF system.

In other words, if you had a CF lighting system that could deliver equivalent light levels to your corals you'd have to be using far more wattage/lamps and you'd actually be generating MORE overall heat, not less.

Because MHs generate all their heat in a small concentrated area vs. distributed along a large surface area (tube) like CFs the common misconception is that they are producing more heat overall. That's not necessarily true.

HTH

 

[holry7778]

Interesting thanks for the quick reply

 

[Anonymous]

Most do use CF or MH for their reef systems.

For my 55g I have ~350-400 watts using NOs and cheapie utility fixtures. Total cost with tubes is about $50 or so. I also use a glass top to keep the saltwater away from the fixtures. But then I am the exception not the rule. (And I am overdriving some of those tubes).

Open brain, zoos, pulsing xenia's, and sps's seem to be doing fine.

So MH of CF are the usual way of doing things. But with a 4' wide tank excellent results can be had with 4' fixtures. Personally I like the idea of having the light spread out over the entire top of the tank as opposed to the more concentrated MF type lighting.

Of course if you had a south facing window all you would need is some lights to see the tank at night. But most of us are not the lucky.

 

[Juck]

>>I would like to keep (in the long-term) an
>>assortment of SPS corals

There's the end of the discussion right there,, you'll need MH for that.

2x175 should work fine, though 250's would be better,, especialy if you're gonna have clams on the sandbed.

I replace my 10k 175w and 250w Ushio bulbs every 10 months or so,,, I believe some 20k bulbs require changing more frequently.

 

[holry7778]

So would two 10,000k 400w MH be oer kill then?

 

[Juck]

Well,,,if you are going the SPS route, can afford the electricity and can deal with the heat then I don't think there's anything wrong with 400 watters over a 55.

 

[ticker]

anyone have something to say about HQI MH bulbs.

 

[Blazin__]

i have a 250 HQI pendant...i like it better that the mogul base... IME their it less colour change to the light as time goes on... and i hear that they are supposed to put out more lumens than the standard mh

 

[myreeef]

I would suggest 3-5 lower wattage MHs all with 2 or 3 different color temperature bulbs. If you use any 20K MHs (IMO) you shouldn't need to use any actinics, as the 20K are plenty blue.

If you also use 14K MHs and/or 10K MHs you will be hitting your corals with more color temp spikes, which from what I can see in my tank has benefited growth, coloration and fluorescing of my corals.

I also found that when I only used one color temp bulb, the lighting seemed harsher to my eyes over longer periods of watching my tank... now that I am using 3 different color temps, I find the lighting more pleasing (at least to my eyes)

I used to use actinic VHOs with 10K MHs, now I only use MHs... but it's all a matter of taste, what you originally suggested should also work.

 

[ZooKeeper1]

3-5 metal halides on a 55 gal tank. Geeze 2 250's will be fine. Remember white light contains all the spectrum, so why the need for all the different colors? Also lower wattage bulbs dont have the intensity needed for sps corals. Anything less than 175's and your wasting your money on electricity. Even 175's are borderline
It seems everyone wants to get away from the daylight colors, when the fact is that the most PAR, and the fastest growth comes from a 6500k light.