How do you know when you need to replace your Metal Halide Lamps ?

[Avalanche Wolf]

I was finally able to upgrade my aquarium lighting to Hamilton Technology ~ Metal Halide Lamps 3 x 250 Watt + 96w Power Compacts .

I was told there was a few months left on the bulbs but from tanks I have seen it seems that date has expired.

The system was bought with 2x250w 10k and 1x175w 20k lamps in it along with 2x96w PC attinics

When the attinics are off the tank is VERY yellow , with them on it is more of a white balance with a tad bit of blue.

I am concerned with this since my SPS frags only really seem to like it on the bottom of the tank ( 100 Gallon AGA ) even though the research I have done says these corals should only be placed mid to mid/high in the tank as they need a huge ammount of lighting.


So if a person without a date of first turned on figure out when a MH lamp needs to be replaced ?

[Sk8r]

I don't know Hamilton by experience. In general, my lfs tells me they're good for about 9 months, and the actinics are good for about 6 months. I let mine go overlong without replacing and am very sorry. It hurt. My lfs suggests writing the date on which the bulb was installed in magic marker on the end of the bulb, so you can tell later. Or make a note in your online scheduler.

[Avalanche Wolf]

Going to start hunting around tomorrow for new bulbs.

[Sanjay]

Best way is to invest in a PAR meter and monitor your lamps. All lamps do not degrade in the same manner.

General rule of thumb is about a year on 10K, about 9 months or less on 20K, and longer on the 6500K lamps. But remember this will also differ for brands.

sanjay.