Lamp life of 20K MH

[dwdenny]

Any one got a idea 6 months a year? I was reading on RC that at 3 months :blink they will lose 50% of their light production!!!!

[Reef69]

Sanjay Joshi uses bulbs for over 2 years, LOL

I change mine every 11-12 months..

[dwdenny]

See that is what I thought. But I could find that out for sure so I asked. lol I am going to email him or post in his RC lighting forum and ask to get a better idea there. I know he would be the one to ask and get the best answer. Thanks

[alton]

With a poor ballast I could see it happening. With new electronic ballast and lamps that match, over a year. Of course after 100 hour burn in period MH only start to decline slowly. Matching lamps to ballast is the trick. Some are made for electronic and some for Magenetic. MAAST could purchase a meter and rent it out for a deposit so members could check there light levels monthly instead of having there corals tell them? Hint, Hint. They run about a $100

[discuspro]

Way sweet idea about the meter

[JimD]

I can tell you from exprience that a 20k xm on a magnetic ballast run 9 hours a day will have a usefull lifespan of approximately eight months. I ran these bulbs for a couple of years with 10k supplmentation and at around 7-8 months the color became washed outand not nearly as intense. I wouldnt recommend running them for two years, at least not over an aquarium if you have acros.

[dwdenny]

Well no this will be Zoanthids mainly. I was looking at either a 175w XM 20k or 250w xm 20k on e-ballast for sure. I know the PAR numbers are not there but I am not looking for great growth but steady growth and great color.

[alton]

I am running Coral Vue Reeflux 12K which is very comparable to your 20K. My last couple of pictures in my Image Gallery are under these lamps. This was still with the Mag. ballast, I need to post some with the new Electronic ballast.

[dwdenny]

alton is it really that blue as in the pics? How is it compared to the E-ballast.

[GaryP]

Sanjay Joshi uses bulbs for over 2 years, LOL

I change mine every 11-12 months..

He also uses 6.5K bulbs so he's starting out with 4 times the PAR that you have with a 20K. He runs several bulbs, I think 3-4 on this tank and rotates the replacement so that there are always a mix of new and old bulbs. That's why he is able to let them go 2 yrs. The problem with 20K is that the PAR is low when they come out of the box. The PAR on a 20K is 1/2 of a 10K, and about 1/3 - 1/4 of a 6.5K bulb. If you have a tank with a single MH bulb, you are going to run into problems with a 2 yrs. life span. The other problem you are going to have is that when you replace the bulb you are going to shock your corals with a sudden increase in PAR unless you cut back the time and slowly increase the amount they are getting. I had that happen once when I went from some lousy 14K to XM 10K bulbs. I basically fried the corals with the sudden increase in light.

MH have about a one month burn in period at which point their output is at its peak, after that there is a gradual decrease in output. The question is at what point is there enough decrease to require replacement. That's going to depend on your system. What other supplemental lighting are you using, what replacement rotation you are using for the other bulbs, how long your burn them per day, etc.

[dwdenny]

Gary I knew that I was not going to get 2 years out of a 20k I was just shocked to hear that(still hard to believe) that they will loose 50% after three months on an good e-ballast(maybe that was a Magnetic ballast). I was planning on running them about 10 hours a day. So at 10 months that is only 3000 hours give or tank. Most will last about 4000 or so hours from what I have read(if I am reading correctly). I was looking at the XM or Radium both 20k of course. I think that if I burn them 10 hours a day I will have to replace at 8-10 months. Not that bad I dont think.