MH Lighting Kelvin Ratings Question

[NoSump]

Ninong had provided an outstanding overview of issues such as wattage and Kelvin ratings as they relate to MH lighting.

I have somwhat of a follow-up question that Ninong, or anyone else's help on would be appreciated.

I got what I believe to be a great deal on a Sunpod system that consists of 2 - 150W DE 14000k MH lights, with LED lunar lights. My question is this, Ninong explained that the higher the Kelvin rating, the more bluish the light. I have noticed that most of the combination MH/PC configurations come with 10,000k AND Actinic PC. My plan was/is to run the SunPod along with only the two 96W actinic PCs that come with my current lighting configuration.

However, based on Ninong's explanation of Kelvin ratings, I am wondering if the 14,000K's will require any actinic lighting at all (since they are already at the blue end)?

One last completely unrelated question, l havn't noticed much in the way of discussions regarding UV sterilizers on this site. Are they deemed to be redundent in a well balanced berlin system?

Thanks again.

[mungus728]

I have a 2x150 MH setup. I am currently using 13K Giessman bulbs. I also run 2x110 VHO attinics. Personally I like the look alot better than with the attinics on than without them. It gives the tank a really awsome look. I guess it is all up to personal preference though.

JMO
Brian

[The R/C Man]

I tried a 10K 250W MH supplimented with 2 65w PC actinics over my 25 gallon with a nice balance between the reds, yellows, greens and the blues. Then I decided to swap the spectums around. Now the 250w MH is 20K and the PCs are 6700/10k combination bulbs. The results where almost identical as before and after pictures revealed. However, the 20k spectrum or lower NM wave length will penetrate the water deep than say a 10K bulb. So by make the swap my light instesty increased dramatically down to the corals even if your eye cannot see the difference. Basically I went from 130W of actinic to 250W of pinpoint lighting. I believe this is more benificial for the corals. You will also notice a huge difference between 460nm actinic and 420nm bulbs. The 460 seems to make everything more irridescent.....

[Reefland]

The appearance of the tank is the big driving factor in my opinion. Once you are using halides with quality bulbs, your corals are going to get the light they need (in most standard configurations). The addition of supplemental lighting such as PC or VHO is up to the user. We utilize only 2 - 250w 14k Phoenix over our tank, with no other lighting.

[NoSump]

Thanks guys:

Yes, I noticed a very different appearance to the tank with the MH. Not quite sure I like the "look". I will definately use some actinics to enhance the appearance. Also, every reply mentioned 250W. Although Ninong's overview of MH clearly stated that wattage is not the most significant indicator of a lights intensity - am I coming in too light with two 150W's?. Would I be better off adding 250W's? Thanks.

Chuck

[Reefland]

The wattage of the light is mostly determined by the depth of the tank. For yours, the 150w DE's are fine, with your most light requiring corals placed higher in the tank. 250w would have been better in my opinion, but you are just fine.

[Ninong]

You're OK with two 150w metal halides over a 72-gal bowfront. My previous point about wattage is that not all lamps of the same wattage are equal in effectiveness because sometimes one lamp may put out as much as three times as much PAR (photosynthically active radiation) as another different brand of the same wattage. And, in general, lower Kelvin rated lamps put out more PAR per watt than higher Kelvin rated lamps (i.e., a 6500K 150w lamp will usually have more PAR than a 10,000K lamp and the 10,000K would have more PAR than a 20,000K).

Anyway, you can add actinic PC supplementation to your two 14,000K 150w metal halides if you want to. If it's too blue, just make one of the PCs 10,000K and the other one actinic. You would get more PAR by switching both of the 14,000K halides to 10,000K halides and then supplementing that with two PC actinics.

[Ninong]

The wattage of the light is mostly determined by the depth of the tank. For yours, the 150w DE's are fine, with your most light requiring corals placed higher in the tank. 250w would have been better in my opinion, but you are just fine.

Scott,

I believe what we were talking about previously is that wattage, which simply measures power consumption, is not nearly as important as PAR in choosing a good lamp. I don't think we really got into the issue of lamp intensity and depth of the water column but in his case the 150's should be fine.

Of course, some people, you included, would have gone with 250's.

[wozza]

hello everyone!

so how do you know what lamp has the most PAR?
Would a 10k 250W have more PAR than a 6400 150W bulb?

cheers james

[NoSump]

Thanks guys, very helpful information.

[Reefland]

hello everyone!

so how do you know what lamp has the most PAR?
Would a 10k 250W have more PAR than a 6400 150W bulb?

cheers james

It depends on the bulb and ballast being used. ;)

[wozza]

oh man!!!!!
does anyone care to explain this to me? haha

cheers james

[Reefland]

It is simple, but complicated. The same bulb can have different PAR ratings when driven by different ballasts. That is the easy part. The complicated part is the number of combinations. Try this link:
Sanjay's Reef Lighting Info Pages

[wozza]

Ok thanks...i think i understand enough for the time being, ill look in to it more when the day comes that i can actually afford to buy MH lamps!

thanks, james