I bought this 400 W MH grow light second hand last year. The light is very intense and looks good to me.
But I m troubled about this brown shadow and the white “caps”. Is this bulb still any good or should I replace it ?
I have a non digital ballast that goes with it. Would a digital ballast reduce power consumption ?
Thank you for your inputs !
love & peace from the swiss guy 
If it’s not cracked. It’s good to use. (Can’t say much for longevity but it should turn on and off u til you can get a replacement) a digital ballast will make the startup load smaller. That’s about it. 400w is 400w though mate.
cola
Replace it no matter what, don’t waste time and money on a 2nd hand bulp.
It can be used for 2 grows, or 10 grows you have no idea.
But after about 4-5 flowering cycles, your HID bulps will have lost about 10% of it’s “PAR power”.
A 400W MH should yeald around 300-320 gram dry buds, with a new bulp.
But now let’s take 10% away, simulating a 1 year old bulp.
Thats 30 grams of weed gone, now what do you pay/get for 30 grams of weed?
A new 400W MH bulp will be 25-35€, id prolly not grow if I could buy 30 gr of weed at that price.
I vote for replace it bulbs are cheap in the end
be safe and be well
Dequilo
If the ballast you have is an iron core (magnetic) ballast they run and use a bit more energy and run hotter
I figure if I am running a 400 watt lamp it takes about 10 % more energy to give me 400 watts of light
as a bulb gets old they use the same or a bit more energy but give you less light as they age
I change my bulbs about every 4 or 5 cycles ( high end about 2800 hours) but I do back to back grows
All the best and grow well
Dequilo
