Metal Halide Bulb Question

[KMP]

I'm looking at a metal halide light and you can chose a 10K, 15k, or 20k bulb. What's the difference - lighting spectrum? If so, which would be closer to having metal halide w/actinics?

Thanks.

[cheeks69]

The higher the kelvin the bluer the bulb and of course a big drop in PAR.

If so, which would be closer to having metal halide w/actinics?

I'm not sure if I'm understanding the question it'll all depend on the kelvin of the MH/actinic combo. If your using a 10k bulb with actinics then it would look like a 12 or 14k bulb depending on how many actinics and wether PC, T5 or VHO.

[KMP]

OK, so I should have searched first :-)

10k bulb- sunlight bulb
15k- Half sunlight with some blue spectrum
20k - very blue spectrum

This is a great link also (forget who posted it):

http://www.cnidarianreef.com/lamps.cfm

[cheeks69]

Here's a chart:

[KMP]

we posted at the same time :-)

ok, so i don't have it all figured out yet :-) reference the question, "...metal halide w/actinics" i currently run pc ligts w/day and actinic. i prefer the look w/both running at the same time vs. just the days.

that said, i'm sure metal halide is a differnet ball game than pc's but i'm looking for a similiar look.

now, what you did help me understand is the higher the "K" the less PAR there will be. "Photosynethis something..."

so, that said, the 15K is probably what i'm looking for. happy medium between day (10K) and very blue spectrum (20K). not to mention (through reading) it seems most folks prefer the 12K - 14K.

[KMP]

cheeks, your all over it :-) thank you so much. that chart helps also.

[KMP]

ok, i'm thinking again - watch out.

so, understanding that the higher the "K" is, the lower the "PAR" will be; can you counterbalance "PAR" with "Watts"?

in other words, if a 10K 150w metal halide bulb gives me the PAR i'm looking for - but it is to "white", can i use a 15K 250w metal halide bulb to get the PAR i need?

[Pro_builder]

so, understanding that the higher the "K" is, the lower the "PAR" will be; can you counterbalance "PAR" with "Watts"?

in other words, if a 10K 150w metal halide bulb gives me the PAR i'm looking for - but it is to "white", can i use a 15K 250w metal halide bulb to get the PAR i need?

Yes, that is the idea. But, you electric bill also goes up too, and price for materials. I am running 15K on 250 watt MH lights. You won't get the coral growth from a 15 or 20K bulb that you will from a 10K, but the corals seem to have more color under a 15K then a 10K. Hope this makes sense.

[KMP]

that makes total sense troy. thank you.

[Jorgens]

The other thing to consider on color is the manufactureer of the bulb. Some people claim a ushio bulb is more "yellow" than an xm bulb of the same k rating.

I have seen coralife 10ks vs Ushio 14ks

The coralife we're a whiter color and ushios's we're slightly more yellish.

Another factor that seems to be making a difference is ballast type. magnetic vs electrical but I have no exp with that one. Just here-say and rumor...

[Pro_builder]

The Electronic ballast will produce a whiter light that is closer to the actual color rating of the bulb, since it is more eficent than the magnetic ballast. They also run a little bit cheaper on the electric bill.

Yes, all bulbs are different from different manufacturers, even though they are of the same Color rating. Why this is I'n not sure, but they are.

[burning2nd]

diffrent brand bulbs will not be the same color (look)

you will have to test em out...

[aquaman3680]

I personally like the 12K Reeflux bulbs! They are great, great color and growth!

Matt