I wonder when it truly is time. The spectrum we are wanting on the ladies is between 400 and 700 (sort of so I'm reading) however in that spectrum as the bulb ages it looses both the spectrum and intensity that the girls want.

In my checking around I have come across two different meters that I think are often referred to a PAR meters. Now first of all I am a real newbie and don't want to appear as an expert or that I am talking out of my arse.

It seems to me we should be able to check our bulbs with these meters AND also check the lighting quality near our plants to see if our lighting/plant placement is correct.

How long do you need to leave a light on before it starts to emit the full spectrum. One minute, ten minutes??

Has anyone had experience with this and if so what is your proceedure and what meter do you need, how much and where did you get it.

Here are the instruments I found so far

http://www.apogee-inst.com/pdf_files/Q_Meter.pdf

http://www.licor.com/env/Products/Se...troduction.jsp
http://www.licor.com/env/Products/Se...escription.jsp

Thanks for everyone's help.

With the cost you get a back up and wait till she's dead and don't turn on no mo

Well that's me during tuff times
O and Welcome !

Attached Images

deadbulb.jpg (44.0 KB, 4 views)

Two grows and then bulb is moved to 'back-up'.

I figure at a few hundred bucks it's worth it to test the bulbs and pitch them when they are truly done. Also that bone yard of old bulbs could have a few gems in them.

Metal Halide bulbs lose strength much faster than HPS. Way faster. HPS bulbs can go 18000 hours,( 10 grows +) and still be putting out 90% of original rating.

I use my 600w HPS bulbs for 12-15 months. I try to change it once a year but sometimes it takes a little longer to get a new one. You can get a light meter to check the intensity if you want to be sure.

im buying a light meter my next time i purchase from my grow store
going to get the digital one
that way if i test the bulb day one (keep a log maybe) and then test again after each grow we can get an idea on the output of the bulb and how much and how fast they degrade
another question off topic......
do digital ballasts produce more lumens than standard ballasts for the sme wattage and bulb?

From what I understand measuring lumens will not give you the information you need to know to determine if there is usable spectrum left in a bulb.

A digital will run the bulb at peak efficiency for longer.
When a bulb is 'done' with a digital, its done.

Two grows and its time for a new bulb. Not so much with vegging
but the flower bulb should be changed out every two grows.

I dont know if it is right or not but I usually use HIDs for about a grow and a half then I replace em. Hope this helps but you will probably hear different. I just try to keep up on it with light meter readings and keeping records to determine the lumen diminishment. This also helps me when it comes to sampling different bulbs to find the best ones for the buck. The Hortilux Lamps seem to be about the best overall out of trying several different ones. Lot's of other good bulbs out there I know I am still sampling.
Peace Always,
Med

__________________

I run two 400 watt hoods. Over the years I've tried just about all the major brand bulbs out there. What I've come to realize is the hype some bulb manufactures claim is mostly a wash. I've settled on Phillips and buy them at Home Depot for roughly $22.00 bucks a pop. Thats cheap enough I can replace the bulbs for every grow. So, the end results for three plants looks like...
IMG_4368.jpg

Peace

420EDGE

If luminous intensity has not dropped, and "usable spectrum" is not present, what kind of light would the bulb be emitting exactly?



I change my HPS bulbs out every 2 years, because The 600 watt Eye Hortilux Super HPS will put out over 90% of initial luminous intensity at 2 years or less of 12/12. At 3 years and 6 months of 12/12 the bulb will be at 80% initial lumens. If you want an extra few %, you can change it every 4 months, I'll take 90+% for 2 years.

http://www.4hydroponics.com/lighting...luxeHPS600.pdf

I change my HPS bulbs out every 2 years, because The 600 watt Eye Hortilux Super HPS will put out over 90% of initial luminous intensity at 2 years or less of 12/12. At 3 years and 6 months of 12/12 the bulb will be at 80% initial lumens. If you want an extra few %, you can change it every 4 months, I'll take 90+% for 2 years.

HPS bulbs can go as long as 25000 hours and still be emitting 80% of original power. At 12/12 that's over 5 years...

The Eye Hortilux is rated for 16,000 and according to Hortilux its at 79% @ 3.6 years 12/12 on average. Mileages very, and that's an average so you can always use a meter to get every last month of use out of your light, but I don't mind paying for bulbs every 24 months.