brighter that i was expecting after using leds for years
yeah with 4x 315 in a 5x5 i was a super uniform 1000 umol @18-24" and was too much. did not behave like 1000 mol with LEDs would, it was too intense w/burning and tacoing. maybe all the UV (which the par meter would ignore) stressed them too much. next time im going with a strict 700 umol on the lec setup
penetration is only related to the brightness of a light and the distance, based on inverse square rule. the best penetration (with any light source) is very intense lighting at as far of a distance from the canopy as possible to give you ideal ppf at teh canopy. in other words, t5 at 6" and hps @ 36" can both deliver 700 umol to a canopy. but go 12" down and youve only increased the distance from the hps by 33%, youve increase the distance of the T5 by 300%. does that make sense? if you doulbeled or tripled the wattage of the t5 and hung it at 36 " to get 700 umol at the canopy, it would 'penetrate' the same as the hps does, simple physics (well not 100% simple as it doesnt account for reflected light but you get the gist
ideal light source: sun millions of miles away. equal lighting at top and bottom of plant