Hi Ilan,
It's really hard to guesstimate actual PPFD by just watts/square number without PAR/watts or J/W parameter, but in general we've also observed prolonged flowering times (roughly 10-15 days for 12-14 week Sativas) when switching from 750umol/s m2 to 1000-1050umol/s m2 two years ago - changed 3k Gen5 Citizens to 3.5k Gen4 Luminus CXM22s. Back than I was inclined to think prolonged flowering times were caused by light temperature change from 3k to 3.5k but now I'm not exactly sure.
Cheers,
It's really hard to guesstimate actual PPFD by just watts/square number without PAR/watts or J/W parameter, but in general we've also observed prolonged flowering times (roughly 10-15 days for 12-14 week Sativas) when switching from 750umol/s m2 to 1000-1050umol/s m2 two years ago - changed 3k Gen5 Citizens to 3.5k Gen4 Luminus CXM22s. Back than I was inclined to think prolonged flowering times were caused by light temperature change from 3k to 3.5k but now I'm not exactly sure.
Cheers,