When do I replace my HPS bulb.

This is a curious topic..

I have been using the same hortilux 1000W bulb now for the past 2 years and haven't noticed much (if any) difference.. And there seems to be no exact science to it (as far as i can tell), but many claim that changes every 6 months or annually is ideal..

I'd like to hear/read more opinions on this topic.

And what kind of HPS bulbs have you been using? My bulbs run about $75.00 EA...

Old thread but I thought I would point out that digital ballasts supposedly can counter the effects of lumen loss.

I just compared a brand new Ushio with one that had been used for about 1 year with a lux meter and found no difference...



Regarding the autoflower, those strains are so dang short I would just save bulb money and time and use the HPS the entire time, perhaps with some T5's added in to improve the mix! If redder light makes a plant stretch more, and autoflower strains stay super short since they never vegetate as long.. I think my logic makes sense here although I won't mess with those strains. I'm a control freak, when it comes to the green ladies.