[jed42]

Help! I've had my reef tank set up for a year. I understand that the SunPaq Actinics bulbs should be replace at least once a year but what about the 10K PowerPaq HQI Metal Halide bulb?

Jed 42

[Ninong]

Hi jed42,

Welcome to Reefland!

I'm not familiar with that particular brand but, in general, most 10,000K HQI DE lamps should be replaced every 12 months, assuming 10 hrs/day operation. This can vary depending on brand and wattage. You don't say if you have 150w, 250w or 400w??? I assume they're DE (double-ended) but you didn't say.

Some metal halides (e.g., 400w 20,000K Radium) should be changed every 6-9 months and some (e.g., 400w 6,500K Iwasaki) can go 18 months. It depends on how fast they degrade in intensity and whether they lose intensity evenly across their spectral output.

P.S. -- You could purchase a cheapy submersible luxmeter (about $95) and measure their intensity (ten days after turning them on) every month and keep track of your readings. The reason to wait 10 days before measuring the intensity is because the intensity falls off a lot in the first 10 days. It takes that long for them to break in. Anyway, you would keep track of your measurements every month and then replace the lamps after they have lost 30% or 40% of their intensity, compared to their reading at the 10-day point. Some people like to replace after 30% loss and others like to wait longer.

You could always buy an Apogee PAR meter if you wanted a better measurement but they cost about $400.

[jed42]

Thanks, I'm glad to be here.
My Fixture is an Out Orbit HQI.

!ea. 150watt 10K MH DE
2ea 65watt 460/420 Actinics

[Ninong]

I'm not familiar with that particular brand of lamp but you're probably OK changing them every 12 months. The same goes for the power compact actinics.

[jed42]

thanks for the help.