how often

[msu]

Do metal halide bulbs have to be changed periodically like VHO tubes?

[LowCel]

Are you running single ended or dual ended mh's? I'm pretty sure that the dual ended only have to be replaced every 9 - 12 months. I'm not sure about single ended.

[aberg12012]

The answer is yes... some more wealthy people like to change them more often than others, but it's probably safe to say the color spectrum begins to shift with in 9 months of use. Me, being less wealthy than some other reef addicts, I plan to try and make them last 12 months. (Keeping my fingers crossed... lol)

[msu]

not running MH at the present time but i have been thinking about switching to them. Right now i am running 4, 110 Watt and 2, 160 Watt VHOs. I was thinking about removing the 4, 110 watt VHOs and replacing them with at least 2 250 watt MHs. if the MHs last nine months that would mean i would get 3 more months than i am currently getting with the VHOs and would have 60 more watts.

[msu]

do pulse start MHs bulbs have a longer life than standard MH bulbs?

[aberg12012]

I think alot of it depends on what your keeping in your tank, and how critical it is that you have fresh bulbs. If it weren't for my one clam in my tank, I wouldn't even need the MH, so for me, it makes sense not to worry too much about pushing the bulbs a little past their spectrum life. I also only run my MH 6 hours a day, as I run both VHO and PC as well. Hopefully this will give my bulbs a much longer life, since VHO and PC's are so much cheeper to replace. :)

[msu]

what kind of clam do you have? we have kept a crocea under VHOs only for about six months. it appears to be health and its color looks great but it is placed about 6 inches under the top of the water.

[MattG]

halides typically last a year. this can change depending on the color temperature or if its SE/DE. something like an iwasaki 6.5k is going to last alot longer then a 20k radium.

[msu]

forgive me but what is SE/DE

[MattG]

single ended

double ended

[msu]

Is there a difference in efficiency between SE and DE?

[MattG]

DE are more efficient(higher par) because a better reflector can be used.

[LowCel]

I have heard that a 250 de is close to being equivalent to a 400 se. Unfortunately I don't have any proof of this right now. :(

[MattG]

ask and yee shall recieve :d

http://www.advancedaquarist.com/issues/feb2004/feature1.htm