I finally got around to buying replacement T5 lamps that are 20 months old. I’m replacing one lamp a week after doing a 50 hour burn in on the new ones to avoid any sudden spikes in lighting. I was curious about the difference in light output so I pulled out to old lux meter.
Not a hugely scientific study, but something to record. I’m placing the meter dead center and about 6 inches in from the front glass since it is an easy spot to reproduce using my lid and I’m measuring at 11A each day
Start: The old lamps put off 19,170 lux.
Lamp 1: Blue Plus, now at 20,200 lux. (~5.4% increase)
Lamp 2: Blue Plus, now at 20,800 lux (~8.5% increase)
Lamp 3: Coral Plus, now at 25,900 (~35.1% increase)
Lamp 4: Purple Plus, now at 26,000 (35% increase)
I’ll update again in a week when I put the next new lamp on.
EDIT: I’m expecting more of a change when I swap in the new Coral Plus bulb since the blues seem to hold their spectrum and output well, but the fuller spectrum ones don’t and this one is almost double the recommended replacement age.