MH Lighting question

[Mytag]

Hi, I have a 48"X18"X12" heavily planted tank. At present I am running a
150watt MH light with two single 30watt fluros.
The MH is apparently 5500K and the two fluros are 6000k each.
What I would like to know is if I go to a higher rated Kelvin for the MH
will it affect the plants too greatly? And what rating do people suggest?
The 5500K MH throws off a yellowish/ orange colour and Id like to have a
more whiter colour in the tank, as it sometimes looks like the plants are
growing in pee!!! (LOL... I hear you!)
I know a lot of people do not like MH, mainly because of the heat, but the
tank is well ventilated and I like the point-of- light effect that you get
with MH. I am running CO2 also (so only the slightest ripple on the surface)
The plants I have are all growing well.
Thankyou in advance.
Michael

[Nick Wise]

Mytag wrote:
> Hi, I have a 48"X18"X12" heavily planted tank. At present I am
running a
> 150watt MH light with two single 30watt fluros.
> The MH is apparently 5500K and the two fluros are 6000k each.
> What I would like to know is if I go to a higher rated Kelvin for the
MH
> will it affect the plants too greatly? And what rating do people
suggest?
> The 5500K MH throws off a yellowish/ orange colour and Id like to
have a
> more whiter colour in the tank, as it sometimes looks like the plants
are
> growing in pee!!! (LOL... I hear you!)

Long story short, NO.

The color temp will not affect plant growth. The only difference is
how it appears to the human eye. If you don't like the color of the
5500k bulb try a 6500k.

Nick

[Drew_Y]

I run a MH HQI lamp with metal halides. I do grow palnts with T5
Daylight bulbs. T5 6500 are much whiter than 6500 MH bulbs in my
opinion.

Kelvin temperature is very subjective and will only effect viewing
experience. Some will argue red/yellow bulbs can enable alage but this
has not been my experience. I prefer 10K bulbs on my reef tank, but
have found brand names within the 10K range to be very different.
Ushio has a yellower apppearance than aqualine 10 K bulbs.

I would definately go with a 10K bulb with your set up, but the reasons
will be for personal choice only.

[Michael J Conboy]

>What I would like to know is if I go to a higher rated Kelvin for the MH
>will it affect the plants too greatly? And what rating do people suggest?

Anything on up to around 12000K should be OK. 20KK marine reef bulbs
might not have enough red for some plants, although lower-light plants
would do fine.

>The 5500K MH throws off a yellowish/ orange colour and Id like to have a
>more whiter colour in the tank, as it sometimes looks like the plants are

I found some 6500K bulbs to give too green of an effect, what with all the
greenery in the tank. But your tastes may vary. 10KK bulbs definitely
will not be too green, but as was posted the actual color effect can vary
among the brands and what ballast is driving them. Some are blue-white
but others purplish, containing more reds with the blue. You might find
some "trial-priced" bulbs on Ebay or the reef sites.

Mike