lighting

[SqueakyClean]

How often should you chang metal halides in a reef?
What about t5 ho's?

[bderen]

I'd say about 9-12 months for the halides and about 18 months for T5s. If you have a fixture with multiple bulbs do not replace all bulbs at the same time but replace a one/few at a time over a period of weeks as not to shock inhabitants. I currently have a fixture with 12 t5s and when the time comes (end of the year) I will change 2-4 bulbs at a time, with newer bulbs being installed every two weeks until all 12 get replaced.

Actinic bulbs however usually don't last as long as 10K bulbs and some people recommend replacing as soon as after 12-14 months. Still much better than changing T8 or T12 every 9 months.

[alazandv]

I change my T-5 every 18-24 months. Usually they fail after 24 months anyway and have to be replaced. Remember not to change all the bulbs at once but stretch it over a period of few weeks. I use sharpie to mark the bulbs that were already replaced so that I don't replace the bulbs I just changed couple of weeks earlier and leave the old ones in there.

[fishtank1980]

I change my ATI bulbs in my 6 bulb Tek light fixture every 10-12 months.... I have a mixed reef...

[hrhladyvic]

Originally Posted by alazandv

I change my T-5 every 18-24 months. Usually they fail after 24 months anyway and have to be replaced. Remember not to change all the bulbs at once but stretch it over a period of few weeks. I use sharpie to mark the bulbs that were already replaced so that I don't replace the bulbs I just changed couple of weeks earlier and leave the old ones in there.

really? stretching it out works better, i though that messes up the ligt spectrum

[stevem]

you should not change them all at once, you can burn your corals. Space out the changes

[xoomer]

Originally Posted by hrhladyvic

really? stretching it out works better, i though that messes up the ligt spectrum

If you were to listed to manuafacturers they'd tell you to change it every 2 weeks. I simply don't believe it and change it every 18 months. I've not had problems because of this with algae blooms or anything else.

[stevem]

what do you mean every 2 weeks.

[xoomer]

Originally Posted by stevem

what do you mean every 2 weeks.

I exagerrated so you get my point. They'd like for you to change your bulbs as often as possible so that they make more and more $$$. Recently I purchased a full set of T5s (12 bulbs) for my Current fixture at a cost of nearly $300.

[stevem]

Almost what some fixture go for

[xoomer]

You bet.

[rdebonis]

Rather than buy expensive new light bulbs on a set schedule, would it be more advisable and less expensive in the long run to purchase a good light meter, check the lights on a regular basis and replace them when the illumination reaches a certain level? I'm sure you can find these light levels for various setups in books and on the Internet.

[xoomer]

Originally Posted by rdebonis

Rather than buy expensive new light bulbs on a set schedule, would it be more advisable and less expensive in the long run to purchase a good light meter, check the lights on a regular basis and replace them when the illumination reaches a certain level? I'm sure you can find these light levels for various setups in books and on the Internet.

That's an additional expense Bob. At 18 months old, these bulbs are certainly past their usefull life, hence the need to replace them in a staggered fashion as not to "burn" corals.

[stevem]

there have been so many test published, not just my manufacturers, but authors and reef experts. The results are always the same give or take a month