Metal Halide Ballast Question

Salt_in_MyBlood · 10/09/2009, 03:52 PM

Just wondering, may be a stupid question but if not it will be very helpful. i have a 400W electronic ballast, can you strictly run 400W bulbs or is there a way to split the output to run two 250W bulbs? not sure if it is possible but i can hope.

Jaycen B. · 10/09/2009, 04:24 PM

That ballast will only run a 400W bulb that is it.

Salt_in_MyBlood · 10/09/2009, 04:26 PM

thank you, that is all i needed to know. i am looking to put it on a 21 inch high tank, just dont want to much light that will bleach everything

xJake · 10/09/2009, 05:14 PM

You can't *split* the output, but you don't have to strictly run 400w bulbs. You can run 250w bulbs (or lower wattage, although I wouldn't suggest it) on a 400w ballast - this is known as 'overdriving.' By overdriving the bulb, you increase the light output, but it's still a lot less than an actual 400w bulb. The only drawback is that overdriving shortens the usable lifespan of the bulb, but it could be done as long as you don't mind the replacing the bulbs a bit more often.

Jaycen B. · 10/09/2009, 05:37 PM

Or the bulbs exploding in your face.

kfisc · 10/09/2009, 05:45 PM

Not a good idea to mismatch halide bulbs and ballasts.

xJake · 10/09/2009, 06:46 PM

Okay, I did some more reading, and it seems I need to retract my earlier post. I was thinking of T5 bulbs not metal halides. It seems metal halide bulbs do have a very high risk of exploding when overdriven, as Jaycen B. mentioned.

I would stick with only 400w bulbs.

10/09/2009, 03:52 PM	#1
Salt_in_MyBlood Registered Member Join Date: Feb 2009 Location: Toronto, Canada Posts: 76	Metal Halide Ballast Question Just wondering, may be a stupid question but if not it will be very helpful. i have a 400W electronic ballast, can you strictly run 400W bulbs or is there a way to split the output to run two 250W bulbs? not sure if it is possible but i can hope. __________________ New Tank setups should be covered under the renovation tax credit.... hahaha

10/09/2009, 04:26 PM	#3
Salt_in_MyBlood Registered Member Join Date: Feb 2009 Location: Toronto, Canada Posts: 76	thank you, that is all i needed to know. i am looking to put it on a 21 inch high tank, just dont want to much light that will bleach everything __________________ New Tank setups should be covered under the renovation tax credit.... hahaha

10/09/2009, 04:24 PM	#2
Jaycen B. Registered Member Join Date: Aug 2009 Location: GA Posts: 265	That ballast will only run a 400W bulb that is it.

10/09/2009, 05:14 PM	#4
xJake Registered Member Join Date: Nov 2006 Posts: 1,385	You can't split the output, but you don't have to strictly run 400w bulbs. You can run 250w bulbs (or lower wattage, although I wouldn't suggest it) on a 400w ballast - this is known as 'overdriving.' By overdriving the bulb, you increase the light output, but it's still a lot less than an actual 400w bulb. The only drawback is that overdriving shortens the usable lifespan of the bulb, but it could be done as long as you don't mind the replacing the bulbs a bit more often.

10/09/2009, 05:37 PM	#5
Jaycen B. Registered Member Join Date: Aug 2009 Location: GA Posts: 265	Or the bulbs exploding in your face.

10/09/2009, 05:45 PM	#6
kfisc Registered Member Join Date: Nov 2003 Posts: 2,020	Not a good idea to mismatch halide bulbs and ballasts.

10/09/2009, 06:46 PM	#7
xJake Registered Member Join Date: Nov 2006 Posts: 1,385	Okay, I did some more reading, and it seems I need to retract my earlier post. I was thinking of T5 bulbs not metal halides. It seems metal halide bulbs do have a very high risk of exploding when overdriven, as Jaycen B. mentioned. I would stick with only 400w bulbs.