When to replace mH bulb?

AliKat · 10/19/2007, 12:26 PM

As many of you probably know, I inherited an older tank when an acquaintance moved. The problem is I have no idea how old the mH bulb is. In the past, I have not had mH lighting systems on my aquariums, so I know very little about it. Is there a way to know when the mH bulb needs to be replaced? Do I just wait for it to go out, or is it best to replace it every few months or so?

I'd prefer not to buy a new bulb if I don't have to. Thanks!

skippy2 · 10/19/2007, 12:41 PM

Can't you ask your friend how old the bulbs are? I replace my reeflux bulbs every 9 months if that helps.

AliKat · 10/19/2007, 01:00 PM

She was more of an acquaintance, and I'm not sure how to contact her. :-(

skippy2 · 10/19/2007, 01:19 PM

What I would do just to be on the safe side is buy new bulbs. Keep track of the purchase date so you know when to replace them again.

AliKat · 10/19/2007, 01:25 PM

Okay, another beginner's question...

I have the type of mH bulb that only screws in on one side (single-ended). What kind of bulb (as in wattage, color, etc.) do I want to get to replace it? The fixture has a place for one mH bulb and two VHO actinics.

Just looking at all of the different kinds of mH bulbs, I'm a little overwhelmed! Thanks for your help.

MJAnderson · 10/19/2007, 02:26 PM

MH lose more ouput in the first 3 months than they will lose in the next 12 months. People replace their bulbs way too often.

You need to replace it with a similiar wattage. They aren't like house lamps where you can drop in a 40w or a 60w bulb. They usually come 70w, 150w, 175w, 250w, 400w. Knowing which you have will help.

AliKat · 10/19/2007, 02:31 PM

I don't suppose the wattage is written anywhere on the bulb, by any chance?

BurntOutReefer · 10/19/2007, 03:16 PM

should be...and/or Model number....worst case...get an Electrician friend to find out output wattage across the Mogul....

AliKat · 10/19/2007, 03:29 PM

And my father happens to be an electrical contractor!

BurntOutReefer · 10/19/2007, 03:38 PM

well......there you go then.

DarG · 10/19/2007, 03:45 PM

Wattage may be on the ballast if you cant find it on the bulb.

mcclandy · 10/19/2007, 04:50 PM

try reading through the metal halide bulb and ballast FAQ at the top of the equipment forum (this forum). it will answer serveral newbie questions

gary faulkner · 10/19/2007, 04:58 PM

Quote:

Originally posted by MJAnderson
MH lose more ouput in the first 3 months than they will lose in the next 12 months. People replace their bulbs way too often.

You need to replace it with a similiar wattage. They aren't like house lamps where you can drop in a 40w or a 60w bulb. They usually come 70w, 150w, 175w, 250w, 400w. Knowing which you have will help.

I agree, but how often would you say, then 18 mo? 24?
My 250s are about a year old and I don't want to change them out now just because someone says I ought to.

DarG · 10/19/2007, 06:15 PM

I think that the best thing to do is watch your tank. You know your critters. Are they looking healthy, growing? As long as your corals are remaining healthy and / or continuing to grow as they have been and/or there is no nuisance algae growth that you can definitely attribute to a spectral shift in the bulbs, then keep the bulbs you have. Without a way to measure spectrum and par and compare with new bulbs after break in, there is no definitive way to know when exactly to replace the bulbs. Knowing your tank is the best way IMO. Within reason of course ... 5 year old halides are probably toast if they are still lit ...

AliKat · 10/19/2007, 06:17 PM

Good point. My corals look very happy, so I guess it's not time to replace yet.

10/19/2007, 12:26 PM	#1
AliKat Registered Member Join Date: Sep 2007 Posts: 590	When to replace mH bulb? As many of you probably know, I inherited an older tank when an acquaintance moved. The problem is I have no idea how old the mH bulb is. In the past, I have not had mH lighting systems on my aquariums, so I know very little about it. Is there a way to know when the mH bulb needs to be replaced? Do I just wait for it to go out, or is it best to replace it every few months or so? I'd prefer not to buy a new bulb if I don't have to. Thanks!

10/19/2007, 12:41 PM	#2
skippy2 Registered Member Join Date: Dec 2002 Location: S.W. Michigan Posts: 3,205	Can't you ask your friend how old the bulbs are? I replace my reeflux bulbs every 9 months if that helps. __________________ Peggy Current Tank Info: no tank

10/19/2007, 01:19 PM	#4
skippy2 Registered Member Join Date: Dec 2002 Location: S.W. Michigan Posts: 3,205	What I would do just to be on the safe side is buy new bulbs. Keep track of the purchase date so you know when to replace them again. __________________ Peggy Current Tank Info: no tank

10/19/2007, 04:50 PM	#12
mcclandy Registered Member Join Date: Sep 2002 Location: Ames Posts: 163	try reading through the metal halide bulb and ballast FAQ at the top of the equipment forum (this forum). it will answer serveral newbie questions __________________ DIY GEEK 150 deep display, 50 gallon sump,120 3w LEDs, AquaC skimmer, filter socks, ato Livestock: SPS, LPS, Clams, Softies, fish Regular maint: keeping it simple with bi-weekly water changes Current Tank Info: 29 gallon sps, lps, shrooms, zoas, remora skimmer, T5's, no sump, dose limewater nightly

10/19/2007, 01:00 PM	#3
AliKat Registered Member Join Date: Sep 2007 Posts: 590	She was more of an acquaintance, and I'm not sure how to contact her. :-(

10/19/2007, 01:25 PM	#5
AliKat Registered Member Join Date: Sep 2007 Posts: 590	Okay, another beginner's question... I have the type of mH bulb that only screws in on one side (single-ended). What kind of bulb (as in wattage, color, etc.) do I want to get to replace it? The fixture has a place for one mH bulb and two VHO actinics. Just looking at all of the different kinds of mH bulbs, I'm a little overwhelmed! Thanks for your help.

10/19/2007, 02:26 PM	#6
MJAnderson Premium Member Join Date: May 2006 Location: East Bay, CA Posts: 2,633	MH lose more ouput in the first 3 months than they will lose in the next 12 months. People replace their bulbs way too often. You need to replace it with a similiar wattage. They aren't like house lamps where you can drop in a 40w or a 60w bulb. They usually come 70w, 150w, 175w, 250w, 400w. Knowing which you have will help.

10/19/2007, 02:31 PM	#7
AliKat Registered Member Join Date: Sep 2007 Posts: 590	I don't suppose the wattage is written anywhere on the bulb, by any chance?

10/19/2007, 03:16 PM	#8
BurntOutReefer Registered Member Join Date: Nov 2005 Location: Granada Hills Posts: 4,376	should be...and/or Model number....worst case...get an Electrician friend to find out output wattage across the Mogul....

10/19/2007, 03:29 PM	#9
AliKat Registered Member Join Date: Sep 2007 Posts: 590	And my father happens to be an electrical contractor!

10/19/2007, 03:38 PM	#10
BurntOutReefer Registered Member Join Date: Nov 2005 Location: Granada Hills Posts: 4,376	well......there you go then.

10/19/2007, 03:45 PM	#11
DarG Registered Member Join Date: Dec 2006 Posts: 5,515	Wattage may be on the ballast if you cant find it on the bulb.

10/19/2007, 06:15 PM	#14
DarG Registered Member Join Date: Dec 2006 Posts: 5,515	I think that the best thing to do is watch your tank. You know your critters. Are they looking healthy, growing? As long as your corals are remaining healthy and / or continuing to grow as they have been and/or there is no nuisance algae growth that you can definitely attribute to a spectral shift in the bulbs, then keep the bulbs you have. Without a way to measure spectrum and par and compare with new bulbs after break in, there is no definitive way to know when exactly to replace the bulbs. Knowing your tank is the best way IMO. Within reason of course ... 5 year old halides are probably toast if they are still lit ...

10/19/2007, 06:17 PM	#15
AliKat Registered Member Join Date: Sep 2007 Posts: 590	Good point. My corals look very happy, so I guess it's not time to replace yet.