when to replace m/h bulbs

[2boyz]

i have 2 175w metal 12k kelvin. they've been on my tank for 6 months now,when should they be replaced? i also have 4- 55w. florecent compacts that have been used for the same amount of time. every thing in the reef looks good and i don't want to loose anything from lack of lighting.

 

[mr . salty]

They are probably getting close.They can sometimes be streached for up to a year,but this depends on how long per day you run them.
When it's time to replace them they will start to loose thier blue,and look more white or yellow.
You could get new bulbs now,and put one new one in,,,then compare the color diference between old and new...If there is no diference then put the old one back in for a couple months...This way you will already have the replacements when they are needed...

 

[richard rendos]

I ran 12K's for about three years and replaced them about every 8-9 months. I noticed a tremendous color difference as soon as I replaced one of the bulbs. It's hard to tell until you compare the new and old next to each other...then it is unmistakable.