A question.
How do high pressure sodium bulbs tend to burn out?
I've used a 400 W MH fixture for several years. I've replaced a few MH
bulbs and they just burn out like any other bulb. Three or 4 years ago I
got a sun systems fixture with a 400 W MH AND a 400 W HPS together in
the one fixture. I remember thinking how yellow everything looked under
the new light.
This week, all the plants came in. About the 2nd day, I realized the
plants didn't look yellow now. Things looked about the same as the MH
only fixture. I peered under the hood and found the HPS bulb still
working but glowing a deep orange that wasn't very bright.
Is this how they die of old age? Don't even tell me the ballast is going
bad!

Steve

On Thu, 11 Sep 2003 00:57:13 GMT, Steve wrote:

This week, all the plants came in. About the 2nd day, I realized the
plants didn't look yellow now. Things looked about the same as the MH
only fixture. I peered under the hood and found the HPS bulb still
working but glowing a deep orange that wasn't very bright.
Is this how they die of old age? Don't even tell me the ballast is going
bad!

MH and HPS bulbs lose intensity over time and should be replaced every
12 - 18 months. It's hard to see by eye, but if you check the
intensity with a light meter when the bulb is new and then after 12
months, you will see quite a drop.

deg

I suppose it's possible it's just a matter of lost intensity. Really
extreme if so. If I hold my hand up to hide the MH bulb from my eyes, I
can look right at the HPS bulb without hurting my eyes. (not that I look
for more than a brief moment.)
I guess it doesn't really matter. My next step is to buy a new bulb or 2
no matter what. It's just that when my MH bulbs have died, they just
burned out without an intensity drop that was obvious to the eye. This
HPS bulb can't be putting out more than 10% of what it should.

Steve


Dewitt wrote:

..........
MH and HPS bulbs lose intensity over time and should be replaced every
12 - 18 months. It's hard to see by eye, but if you check the
intensity with a light meter when the bulb is new and then after 12
months, you will see quite a drop.

deg

Steve,

I agree with the 12 month replacement cycle. When I grew under lights I ran
my bulbs for 18 months or so and then replaced them all at once. I could
really tell the difference when the new bulbs were replaced.

If you wait for these things to burn out you will be wasting energy and not
getting the full benefit for your plants.

Good growing,
Gene


"Dewitt" wrote in message
...
On Thu, 11 Sep 2003 00:57:13 GMT, Steve wrote:

This week, all the plants came in. About the 2nd day, I realized the
plants didn't look yellow now. Things looked about the same as the MH
only fixture. I peered under the hood and found the HPS bulb still
working but glowing a deep orange that wasn't very bright.
Is this how they die of old age? Don't even tell me the ballast is going
bad!

MH and HPS bulbs lose intensity over time and should be replaced every
12 - 18 months. It's hard to see by eye, but if you check the
intensity with a light meter when the bulb is new and then after 12
months, you will see quite a drop.

deg

Well, I got my new 400 W bulb in the mail on Tuesday. I put it in the
next day and things still don't look right. The bulb just isn't bright.
The light that falls on the plants still looks white, just like my pure
MH light in the other room of the basement. When the combo fixture was
new, the light made the plants look a funny yellow color. The sodium
bulb isn't putting out enough light to do that now.
I guess I need a new ballast. :-( Does anyone happen to know if the
output of a HP Sodium ballast can be tested with an electronics meter?

Steve


Steve wrote:
A question.
How do high pressure sodium bulbs tend to burn out?
I've used a 400 W MH fixture for several years. I've replaced a few MH
bulbs and they just burn out like any other bulb. Three or 4 years ago I
got a sun systems fixture with a 400 W MH AND a 400 W HPS together in
the one fixture. I remember thinking how yellow everything looked under
the new light.
This week, all the plants came in. About the 2nd day, I realized the
plants didn't look yellow now. Things looked about the same as the MH
only fixture. I peered under the hood and found the HPS bulb still
working but glowing a deep orange that wasn't very bright.
Is this how they die of old age? Don't even tell me the ballast is going
bad!

Steve

Which combo fixture did you get? I just got the Hydro one and am hoping I
don't run into the same problem (mine is a switchable ballast) my HPS bulb
works great, but my MH I have to 'fiddle' with or it doesn't come on. I"m
using MH one week and HPS the next, trying to cover all bets here

--

Hugs,
Molli


"Steve" wrote in message
t...
Well, I got my new 400 W bulb in the mail on Tuesday. I put it in the
next day and things still don't look right. The bulb just isn't bright.
The light that falls on the plants still looks white, just like my pure
MH light in the other room of the basement. When the combo fixture was
new, the light made the plants look a funny yellow color. The sodium
bulb isn't putting out enough light to do that now.
I guess I need a new ballast. :-( Does anyone happen to know if the
output of a HP Sodium ballast can be tested with an electronics meter?

Steve


Steve wrote:
A question.
How do high pressure sodium bulbs tend to burn out?
I've used a 400 W MH fixture for several years. I've replaced a few MH
bulbs and they just burn out like any other bulb. Three or 4 years ago I
got a sun systems fixture with a 400 W MH AND a 400 W HPS together in
the one fixture. I remember thinking how yellow everything looked under
the new light.
This week, all the plants came in. About the 2nd day, I realized the
plants didn't look yellow now. Things looked about the same as the MH
only fixture. I peered under the hood and found the HPS bulb still
working but glowing a deep orange that wasn't very bright.
Is this how they die of old age? Don't even tell me the ballast is going
bad!

Steve

This one Molli:
http://www.growking.com/images/ss7_photo.jpg (I just looked for a
picture and found this one.)
It's a Sun System VII. It runs both bulbs at once for a total of 800
Watts.

Steve
PS I found an e-mail address for the company on their web site:
http://www.sunlightsupply.com/horticulture/index.shtml
I wrote to ask them about the problem. I also noted they have a 5 year
warranty on their ballasts. I'll have to go look and see when I got mine.

molli wrote:
Which combo fixture did you get? I just got the Hydro one and am hoping I
don't run into the same problem (mine is a switchable ballast) my HPS bulb
works great, but my MH I have to 'fiddle' with or it doesn't come on. I"m
using MH one week and HPS the next, trying to cover all bets here