bulb replacement tonight

[iseeweed]

Ok, I am ready to replace my bulbs tonight. I have 2, 250w de MH pendants running 14k hamilton bulbs over my 75g. I run the lights for 8-9 hours a day. I am replacing the bulbs with the exact same bulbs. The bulbs are 7 months old and this will be my first bulb change.

My question is, how should I "break in" the new lights. Should I cut back on the running time? I was thinking maybe running for 4-5 hors a day for a while and then increasing the time? Or, should I just keep them on the same cycle?

 

[Anonymous]

Why are you changing light bulbs after 7 months?

DE bulbs can last up to 18 months. I would change them after 14 months at your usage. I change my SE bulbs every 12-13 months.

To answer the question, I just change them and run as usual. I am not sure if it is Sanjay, but some studies show that intensity and PAR are not effected as much by usage as previously thought. The only difference was that there was a Kelvin shift towards the red spectrum as the bulb aged.

 

[iseeweed]

Why are you changing light bulbs after 7 months?

DE bulbs can last up to 18 months. I would change them after 14 months at your usage. I change my SE bulbs every 12-13 months.

To answer the question, I just change them and run as usual. I am not sure if it is Sanjay, but some studies show that intensity and PAR are not effected as much by usage as previously thought. The only difference was that there was a Kelvin shift towards the red spectrum as the bulb aged.

I decided to change the bulbs because I was getting a red cyano outbreak. I had already did a water change, carbon and GFO.
The old bulbs definitely lost their blue tint over time. I installed the new bulbs and WOW!-what a difference in color. Here is a picture of one of the old bulbs. Looks kinda burnt to me.
My last tank I let a 250DE 10k run for almost a year, and by then it had lost a lot of its intensity. I then changed to a 20k and ended up bleaching some of my corals.
IMO 18m seems way too long :roll:

 

[Anonymous]

While I don't agree with the 18 month strategy for bulbs, depends upon your ballast as well since HQI ballast will overdrive the bulbs and reduce their lifespan compared to an electronic ballast.

All bulbs get that "burnt" look, IIRC it's sputtering of molten metal when the bulbs initially fire. And yeah, I've never liked the life span of Hamiliton 14k bulbs, initially they look nice, but before you know it it's a really dim tank.