I always keep an extra on hand. I bought a light meter just so I could check my 1000w hps output. Have used the same bulb for over 2 years now and there has been virtually no change in lumen output.
killerweed420 Reviewed by killerweed420 on . When do you replace your HPS bulbs? I coming up on the completion of third grow with my current HPS bulbs (600 and 400). Just wondering when they start to lose effectiveness and when you experts say its time to get new one. Feedback appreciated :) Rating: 5