400Wat bulb 250w ballast

[fishdip22]

So I have a ballast that has different settings and was wanting to know if I could get a 400wat bulb and run it on the 250wat setting with out harming the bulb. I know running a 250wat bulb in a 400wat fixture is bad but can I under clock the bulb and then slowly increase the watts over time as the coral gets adjusted to the amount of light?

 

[Breadman03]

I've run mine at 300 for a while and it seemed to work just as well at 250, but I really don't know the long term impact or how much the spectrum may shift at different wattages.

 

[Ron Reefman]

It's just a guess on my part, but like Breadman03, I think spectrum shift may be significant. And running a 400w bulb at 250w just makes me think it's going to shift warmer and more red. But that's just an educated guess on my part.

Good luck.

 

[Cthehentz]

The 400 will appear dimmer and never reach it's 100% output, the envelope will darken sooner and lamp life will be short.

 

[fishdip22]

The 400 will appear dimmer and never reach it's 100% output, the envelope will darken sooner and lamp life will be short.

It's just a guess on my part, but like Breadman03, I think spectrum shift may be significant. And running a 400w bulb at 250w just makes me think it's going to shift warmer and more red. But that's just an educated guess on my part.

Good luck.

I've run mine at 300 for a while and it seemed to work just as well at 250, but I really don't know the long term impact or how much the spectrum may shift at different wattages.

Thank you.

 

[Breadman03]

The 400 will appear dimmer and never reach it's 100% output, the envelope will darken sooner and lamp life will be short.

Not-so-recent paper that concurs with your statement.

http://www.lrc.rpi.edu/programs/NLPIP/lightinganswers/pdf/view/LAHID.pdf