400 watt to 250 watt conversion

[benwildog]

My setup is currently running w/ 2 400 watt mh's and 2 110 watt actinics vho's. If I wanted to switch to 2 250 watt mh's can I simply replace the bulbs? Or does the ballast send 400 watts to the bulbs? My tank is a 110 and is 30 inches deep, but I would like to downgrade to 250's.

 

[zman1]

The ballast at minimum will need to be changed as well.

 

[zanclus]

Originally Posted by Benwildog
My setup is currently running w/ 2 400 watt mh's and 2 110 watt actinics vho's. If I wanted to switch to 2 250 watt mh's can I simply replace the bulbs? Or does the ballast send 400 watts to the bulbs? My tank is a 110 and is 30 inches deep, but I would like to downgrade to 250's.
Why would you want to downgrade ? You need to change your Ballast and bulb. You can use the same reflector and socket.

 

[benwildog]

Just do not have the need for the wattage right now and the power consumption is large. But not worth the cost if I have to replace the ballast anyway. So I will prob just stick w/ the 400's

 

[zman1]

Originally Posted by zanclus
You can use the same reflector and socket.
Unless it's a DE and not Mogul. The sockets are different lengths on DE

 

[benwildog]

good to know thanks for the responses

 

[zman1]

Benwildog,
You may be able to down grade bulb wattage from 400 to 250 and not have to swap ballast. You can't go from a 250w to 400W bulb but down may be possible. I was looking at some ballast specs from AdvanceTransformer for myself and thought of you. If you know the ansi # of the ballast you have now. If it's output voltage is the same or with in the ranges you see between the 400W and 250 watt for the M58 (250) or M59 (400). Probe start usually Mogul. Verify your Ansi number and compare it to what you have and what you want. Having a Ballast that matches output voltage capable of running a larger load like the 400W should be capable of driving a smaller load 250W. Again DE would still be a problem since they are different lengths. No guarantees either way....
Pages 5-24, 5-27 - M58, M59
Pages 5-25, 5-28 (M138 , M153, M89 HQI), (M128, M135,M155,M172,M144)
http://www.advancetransformer.com/up...tion_5_HID.pdf
This column:
Nom
Open
Circuit
Voltage

 

[frozenguy]

you can run a 250mh bulb on a 400watt ballast (most set ups) but you'll burn the bulb quick and it wont burn right and yeah.. its a waste

 

[zman1]

Below is Page 58 of a pocket reference guide from Advanced Transformer. Also a nice troubleshooting section beyond this attached picture.
http://www.eere.energy.gov/buildings...ance_2003a.pdf
Example M58 - M59 - could be operating in a midrange which might work. However, the window of tolerance for each could be out of range for the 250W bulb on a M59 ballast. - again just a probe start example.