View Full Version : MH and T5 life span

06/14/2010, 08:12 PM
Hi all,
I have been having really bad cyno problems and have tried everything from water changes to cutting down on the food, cutting the MH from 10 to 8 hours and nothing seems to help. All my test(s) seem to be fine and I'm starting to wonder if it could be my lights. I have 2 250W double ended HQI 14K and 2 T5 54W (420 and 460) all are about 9 months old on a 60 gal tank. I was getting ready to replace the T5's but I was told by my LFS that the MH need to be replaced about every 6 months, that seems to be a very short life span. I run my MH for 8 hours a day and the T5's for 12 hours a day. Any help would be appreciated.

06/14/2010, 08:17 PM
You should get at least a year to 18 months out of MH's at 8/hrs per day.

Telling you 6 months is nothing more than a ploy to sell more bulbs.

06/14/2010, 08:25 PM
18 months is a long time to go prior to replacing your halide bulbs. The rated life may be that, but the spectrum will shift much sooner than that. That is what causes the problems and the naked eye can't pick that up.

Personally, I like to change my halide bulbs more often that I probably should. That way, I change prior to the spectrum shifting. I like to change about every 8 months although I am sure I could get 10 - 12 months in most cases from the bulbs.

Gary Majchrzak
06/14/2010, 08:29 PM
Hi all,
I have been having really bad cyno problems.
it's not the lights.

06/15/2010, 10:12 AM
its not the lights, tank is still somewhat new. better food prep and po4 managment.

06/15/2010, 10:26 AM
you should change your bulds every year

06/15/2010, 11:22 AM
Actually the tank is about 2 years old. I changed from PC compact to MH about 9 months ago when I started adding SPS corals. This is the first time I have not been able to beat the cyno usually by cutting down on the lighting and food and the use of a Phos remover. I just ordered some new bulbs and MICROBE-LIFT SPECIAL BLEND SUPPLEMENT which I read about in the forum. I have been using activated carbon in my sump, would that cause any of my problems?
I appreciate all the comments, I learn a lot by reading them.


06/15/2010, 02:27 PM
My Ushio 10k has been running for almost 3 years. It should be replaced, but the coral are still growing, so meh.