MH lights - what rating?

[jws444]

Originally Posted by fortheloveofcrabs

Higher K, more watts. Simple. I have a 16 gal nano with a 175 watt 20k and it looks great, and growth is good (1 polyp candy has grown to 19 polyps in 8 months, 1 polyp torch to 4 polyp in 6 weeks). I am upgrading a 400 watt 20k so I can keep SPS corals (I say Josh's cat's paw and fell in love!) But that's my 2 cents... 20k all the way!

-Pauli

The temperature rating of a bulb has no correlation to wattage. A bulb consuming 175 watts will remain the same regardless of the bulb's kelvin rating.

Personally, I find 20k kelvin bulbs are decent looking on well stocked tanks. If you're running a 'bare bone' tank with not much live rock and corals, then you'll get nothing but glowing blue sand. It is really preference. Take up some of the member's offers and go take a look. It's the only real reference you'll be able to get.

[Pan]

you can get 13k bulbs as well...

[TheReefGeek]

It is true, there is greater PAR under whiter light. The more blue, the less PAR, and less coral growth.

NOT always true. XM 20K bulbs are more blue than XM 15K bulbs, but the 20K give off more PAR on the same ballast.

Because you have supplimental VHO actinics for color, I would go with 10K bulbs, I really like the look of my XM 10K with VHO actinic suppliments. If you want to save money and ditch the VHO, go with 20K bulbs. I have XM 20K and they look almost as good as XM 10K w/VHO actinics IMO.