Light Burn or ClaMag issue?

It's perfect, Biobizz is rather tricky to grow with and what you do today won't show for like another two weeks. Having the slightly Nitrogen burned tips perpetually up until the stretch finishes is exactly where you wanna be, if the burned tips fade you're effectively under feeding next week. No cal/mag def, Alc-a-Mic could've helped out if that was the problem. No light burn, crank it up some more if you can, gotta push the light to the max, it's your engine, you can always back off if you overdo it, the plants will tell you when, no need to measure PPFD :) Never flush mid grow when using Biobizz, but do make sure you flush it out well two weeks before harvest, like run at least 10x potsize water through each pot at least once and of course feed pure water for the rest of the grow. Biobizz is notorious for smoking harshly and making black ash if not flushed out properly. You're crushing it, keep on keeping on!