those who use XM 20k on their SPS, how long until a bulb change?

[kevensquint]

I've been using different MH 250 watt bulb combos (SE's) and for now I have XM 10k and XM 20k's. The 20k's are about 8 months old, and I have heard from an "ex-expert" that after 6 months or so, the 20k bulb would be like holding a candle over your tank. From your experiences, how many months will a XM 20k last before things start to change for the worse in there?

 

[steve the plumb]

Don't mention brand names its a NO-NO.Ha Ha.

 

[Ti]

12 months

 

[kevensquint]

Did you just change 'em out because it was a year, or did you see a change in your tank that made you replace them?

 

[woodywoo]

I hear that XM bulbs last and hold there spectrum a good while over 9 monthes I know. I would say about 12 monthes just to be safe.

 

[Znut Reefer]

It also depends on what type ballast you are using. If it's a eballast a yr. HQI they say 6 mos, since the overdrive the bulb I hear.