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View Full Version : How Often Do You Replace Your MH Bulbs


Eric45
01/24/2010, 07:30 AM
I had heard it was ok to go for as long as 18 months before replacing halides, but I just replaced mine after 12 months and the difference quite amazing -- I'd say at least a 30 percent increase in light. In the future, I'm not going more than a year w/o changing bulbs. How about you?

Montreal Ray
01/24/2010, 07:35 AM
Minimum 12 months. Best MH article I've ever read http://reefkeeping.com/issues/2007-04/ac/index.php

I have been in the habit of replacing my bulbs about once a year as is so often recommended. The measurements suggest that this may not be necessary, though. In my aquarium setup, my lighting is suspended by a pulley system, which allows the lights to be easily raised and lowered (see Figure 3 below). Lowering the lamps a few inches can easily compensate for a 25 to 30% drop in lamp output to maintain a consistent light intensity for the corals

I've installed my MH's on a pulley system because of this article. Genius idea

Eric45
01/24/2010, 07:43 AM
Thanks for the article. I'm still going to stick with annual replacement. My eyes tell me the difference is significant.

spleify
01/24/2010, 08:19 AM
I change mine at the 8 or 9 month mark

Mike O'Brien
01/24/2010, 08:20 AM
What bulbs are you using ? IME it's the higher k bulbs that need to be replaced more frequently because of the color shift away from blue. Much easier to see by eye than a loss of intensity. A quality 10 k lamp like AB for example will still appear the same well after a year and still be putting out plenty of par.

I change mine every year. There are a lot of choices and I like to try a new one every year.

mfinn
01/24/2010, 08:46 AM
I change mine every 12 months.

gdsmith56
01/24/2010, 08:49 AM
My info came from an LFS owner and their view was that HQI bulbs needed replacing at the 12m mark while mogul bulbs could go 18-24m between changes. I only had the one 70w HQI with a new bulb at the time so I wasn't to worried about it but does anyone know if there is any validity to this line of thought ?

jbird69
01/24/2010, 09:08 AM
I suppose if the determining factor is when your corals actually start to suffer, you could probably go 18-24 months. If you want to maintain a bulb color and intensity, 8-10 mo.

Rhodan
01/24/2010, 09:17 AM
I try to change every 9 months....But normally it runs into the 12-14 month time frame, or when the coral suffer which ever comes first....Bad hobbist bad bad bad.

Anemonebuff
01/24/2010, 09:22 AM
SE bulbs are usually 9-12 months used at about 10 hours a day. DE bulbs are 12-14 months(not Radiums, change them after 9 months) at 10 hours a day.


I also remember reading an article, that I cannot seem to find, that higher K bulbs need to replaced less often than lower K. That is because the higher K bulbs shift to the red spectrum as they age and tend to have a higher PAR. The suggestion of the article was that you can get away without changing your bulbs for much longer. I change mine after 12 months and am not willing to chance it.

SDguy
01/24/2010, 09:23 AM
I run DE phoenixes on Icecaps. I went two years this last time. It was too long. I have heard you can go more than a year with these though, so next time I'll go 14-16 months...

Stanley-Reefer
01/24/2010, 09:39 AM
WOW! I've been changing my 150 and 250w Phoenix DE every 6 mos! Is that overkill?

SDguy
01/24/2010, 09:56 AM
WOW! I've been changing my 150 and 250w Phoenix DE every 6 mos! Is that overkill?

IIRC someone did some testing, which showed a larger drop in the first few months, and then more leveling off, suggesting unless you change often (like you, or even more frequent) then you should be OK over a year. This is all from memory...don't quote me :D

jbird69
01/24/2010, 10:40 AM
WOW! I've been changing my 150 and 250w Phoenix DE every 6 mos! Is that overkill?

If you still have your old bulbs, you may not have to buy any for a while!!

Crazyc_625
01/24/2010, 11:14 AM
the longest i keep my mh bulb for is a year.

mm949
01/24/2010, 12:01 PM
every six months for me.....

Eric45
01/25/2010, 08:23 AM
Hey thanks for all the replies. It tends to confirm my sense that 12 months is about right. I've been using Ushio 14k 150w's.

HumbleLobster
01/25/2010, 08:31 AM
I run 150w DE phoenix bulbs. I replace them once a year like clock work. If I had a setup where I could raise/lower my bulbs easily I would definitely keep them longer.

Juruense
01/25/2010, 08:53 AM
I change mine when they burn out.

SDguy
01/25/2010, 09:01 AM
I change mine when they burn out.

How long does that take?

ucanto
01/25/2010, 09:16 AM
i have 2 250w SE and change them every 18 months. Buy one every 9 months to offset the change. It does seem that they have a huge drop the first month or so then slowly drop after that. I believe you could go 2 years without changing the bulbs before they take a toll on your corals.

serpentman
01/25/2010, 09:19 AM
It largely depends on the manufacturer and bulb color. You can easily go 18mos with a 10K. However, IME, the higher the Kelvin, the more color shift.

Generally, I look to replace mine at the 1yr mark.

MeuserReef
01/25/2010, 09:57 AM
Im at the 12 month mark this month with my 250W DE Phoenix 14K lamps. I used to run the 150W versions for 16 mos at a time, but am probably going to shoot for 14 months with the 250W versions. I dont have a PAR meter, so really Im just guessing that they need changed. My lamps are only 4-5" off of the water surface, so intensity is likely not an issue as much as the shift in color. Corals look happy though :D

Peter Eichler
01/25/2010, 12:22 PM
My info came from an LFS owner and their view was that HQI bulbs needed replacing at the 12m mark while mogul bulbs could go 18-24m between changes. I only had the one 70w HQI with a new bulb at the time so I wasn't to worried about it but does anyone know if there is any validity to this line of thought ?

Virtually no validity... It really depends on the particular bulb, ballast type, how long of a photperiod someone runs, ambient temperature, and probably a couple other things I'm forgetting. Also, DE does not = HQI. I won't get into all the details in this thread but the term HQI is misapplied quite often in this hobby.

Whisperer
01/25/2010, 01:04 PM
What do you guys do with your old bulbs that are still working? I have accumulated quite a few.

noobtothereef
01/25/2010, 01:13 PM
What do you guys do with your old bulbs that are still working? I have accumulated quite a few.

give them all to me :spin2:

hernluis
01/25/2010, 06:09 PM
i use 175w mh reef optics 20000k, no more than ten months of use on them