150w or 250w Metal Halide?

[Fingers68]

I have two 150w metal halides 10000k and I wonder what the difference might be upgrading to 250w. Given the same water conditions, what sort of growth difference would you realisticly be looking at?

 

[ludnix]

What is the dept of the tank?

 

[Fingers68]

30" I have my lights 6 inchs off the water

 

[JCR's Reef]

It depends on what your wanting to grow, and how fast. I have a 150w on a 30" high and I dont have a problem growing anything. Its even growing the monti caps on the bottom. But their are certain species of coral that will provide higher light that you will have to put right up top of the tank

 

[Fingers68]

Regardless of what is growing, is there a noicable difference between the 150 and 250w?

I have a mixed reef SPS, LPS and softies BTW.

Would be nice to know the difference as there will be a big difference in the electric bill!

 

[Henry Bowman]

At the risk of being sarcastic..

You are going from 300 watts to 500 watts a 60% increase. If you have decent reflectors there is going to be a pretty significant difference in light and power consumption.

IF your tank is doing well and corals are growing, I'd suggest you put the $$ into GOOD bulbs and or reflectors n' be done with it. Furthermore, I'd stick with bulbs in the 10K-12K color range and if it is too yellow for you put some cash into decent actinic supplementation.

 

[Reef Bass]

30" deep? 400w!!!

Or at the very least 250s with Lumenarc reflectors.

 

[Fingers68]

If your saying 400w for each lamp Reef Bass !!! Things are growing fine 800w total seems a little over the top to my humble opinon.

When I say difference, I meen is the % increase relative to the growth for eg 50% more growth with 50% more light power. I think it would not be this case but I am asking the question. I guess only personal experiance of this can answer that one.

 

[Jorober]

For a tank that's 30" tall, I'd definately go with nothing less than 400W. 150W bulbs won't even come close to cutting it, and 250W bulbs will only be good enough light for about half that depth. They'll reach lower than 15", but not very well.

 

[Jorober]

% increase in wattage does not translate into % growth increase. It all has to do with kelvin rating and par rating of the individual bulbs. You can get 250W 10K bulbs that grow corals like crazy in the right situation, but a 250W 20K bulb might not grow as fast as a 10K, but you coral colors will be much better.

 

[Reef Bass]

I agree with it being more about color temp and par than straight up watts. I am running 2 400w MH with 20kK EVC bulbs over a 24" tank with supplemental T5 actinics. I have great color and growth.

You could maybe get away with 250w and a focused reflector, like the Lumenarc, if you aren't wanting fast growth. But know better color could be had, even from the corals up top.