^5s Image Reaper , I don't mean to hijack this thread but I've been using the same 400 watt HPS bulbs for about 2 years now. What is the lumen decline with these bulbs? I believe they start out at about 50k lumens but after one year what , in your opinion is the lumen output?
Deejay2163 Reviewed by Deejay2163 on . How do I tell if a HPS bulb is spent? Please excuse my lack of knowledge when I ask this question, I'm still quite new to this. I bought some 400w HPS bulbs which had been used for approx a week before being replaced with 600's (or at least that's what I was told). I was wondering if there are any visible signs that show the age/usage of a bulb? There are burn/stain marks on the bulb and the white bit inside looks very dark at the edges. Are these signs of age and use? Thanks for any replies. Rating: 5