When to change bulb?

[krustythfreakinclown]

I have a 400W HPS bulb which has been used for 3 grows: about 1 month at 18/6 and 2 months at 12/12, per grow.

When should I change the bulb?

Does the bulb just burn out, or does it give warnings that it is waning?

krustythfreakinclown Reviewed by krustythfreakinclown on 05-29-2006. When to change bulb? I have a 400W HPS bulb which has been used for 3 grows: about 1 month at 18/6 and 2 months at 12/12, per grow. When should I change the bulb? Does the bulb just burn out, or does it give warnings that it is waning? Rating: 5

[knna]

Before failure, if wired correctly, a HPS bulb goes losing output with time. You must change it much time before it fail.

How much time? It depends strongly of the setup. Some combinations of lamps/ballast last longer than others. The best way to know it is measure light output with a fotometer/luxometer (always in same position for same setup). When measure goes below 80% initial lux, its time to change.

Simpliest bust less accurate symtems are change the bulb in a regular basis (one year, for example) or wait to see the yield reduced (the worst option).

So with that time of use, you must going thinking in change the bulb, althought a good HPS system can last 2 years, usually its useful life is about 1 year.

[Bluefunk]

The amount of lumans a bulb emits decreases with age, I once read on overgrow its good practise to replace your bulb once a year with constant use.