BSF Tres Gorillas

The readiness of getting topped is based on how many nodes the plant has and its over all health. Your plant is looking quite healthy. I'd say your good to go, top/prune away. should always aim for 2 min and 3 is ideal for node sites before topping. Anything after three nodes is also ok, just depends on the style your looking to grow your plant into. Best of Luck and Happy Growing.

Could match the same brand as what you have been using in Veg, I like dry amendments in growing, different style of feeding and use vs liquid nutrients. Almost all liquid fertilizers use the same active things things for NPK, but its there extras in them that make them different like PH stabilizers, so they can react to one another like Roberts said. Down to Earth, Dr,Earth, Gaia Green are a few brands I like. Best Of Luck!

Looks a bit like phosphorous deficiency to me. I'd also PH your water to 6.5-6.8 with soil/coir mix vs 6.1 Cant seem to see what your feeding them or any NPK ratios. May just be getting hungry, Good Luck!

I run the fCE4800. I’d normally tell you with out a doubt 100% but you can get away with 75% if you really know what height to have it at.. cuz this thing has excellent photon distribution. IF you’re trying to save money. You could run as low as 75% at maybe 10 inches. If not, just go 100% at 15-18 inches, drop a bit lower if not showing any issues after a few days