I kind of feel like that’s been common knowledge for a while now. Kelvin rating has become entirely subjective. Most led users think of solid royal blue as 20k. I’ve read enough accounts of people switching from LEDs to trying out metal halides and calling the 20k radium bulb too yellow. In the planted tank world the 6500k bulb is considered on the blue end. In the early days of reefing 10k was blue. Opinions change and there’s no real reference standard beyond the Incandescent bulb as 3000k if I’m not mistaken. The radium 20k looks nearly identical to the Phoenix 14k, which is about as blue as the reeflux 12k was. The ushio 14k looked about as yellow as my old xm10k’s. Every manufacturers kelvin rating is different. You just kind of learn what to expect from various options
This is interesting - thanks. That said - how many people are as expert as you and @jda - whose encyclopedic knowledge of bulbs, etc is extremely impressive - who can go out and check 8 bulb types to decide which to order if its going to be based on 'subjective' appearance - as compared so actual spectrum. (I mean I keep seeing spectra posted from different halides as compared to LED's). Just asking




