[mrok12]

The questions are as infinite as the possible choices so I'll try to keep this short. I plan to keep primarily SPS corals and Tridacna maximus clams in a 120 gallon reef. I am leaning toward a combo of metal halides and power compacts. I plan on upgrading the bulbs to at least 10k. Are there any advantages with going with a higher K vs. A higher Wattage bulb in the MH.

MROK12

[Ninong]

For SPS and Tridacna maxima clams in a 120-gal tank, you should choose either 250w or 400w metal halides. You will probably want actinic supplementation of some sort unless you are including 20,000K metal halides in the mix.

There are many possibilities and each has its advantages and disadvantages. If you choose 400w 6500K Iwasakis, for example, you may find that you need a lot of VHO actinics to give you a "nice" final color. This setup would be very hot and very costly in terms of monthly electrical usage. (Don't forget the heat from the 400w ballasts.)

You could consider the 250w 6500K Iwasakis as a compromise as they would require less actinic supplementation and use less electricity. Also, you might even consider using Ice Cap electronic ballasts with these to reduce the total heat that the entire setup will give off in the room.

If you prefer 10,000K metal halides, you have several possibilities. You can get mogul base 10,000K lamps in 250w or 400w sizes, or you could get 250w 10,000K HQI double-ended lamps. The 10,000K lamps would not require as much actinic supplementation to give you a "nice" final color. If you choose the 250w double-ended lamps, you would have approximately the same PAR as with the 250w 6500K Iwasakis. In fact, the 250w double-ended lamps have more PAR than many of the 400w mogul base lamps (except 400w 6500K Iwasakis, of course). One of the nice things about the 250w double-ended lamps is that they require very little actinic supplementation, which reduces your total electrical consumption, and another thing is that you get a lot of PAR for your electrical consumption. The biggest complication is that these lamps may be difficult to incorporate in a standard canopy/hood setup. Most people who choose this option will get a ready-made fixture that is suspended above the tank.

A really impressive way to go would be to use a combination of 10,000K and 20,000K metal halides. This is what Steve Tyree uses over his SPS tanks. This could get a little pricey.

The bottom line is that most people do not have unlimited funds to allow them to go nuts in the lighting department so they end up with a compromise that fits their budget and pleases their eye.

Moving this thread to the Lighting forum.

Ninong