This week the bigger fan leaves has started to yellow and get dark spots on some. I turned the second light a week ago and I'm thinking about some burning or some type of deficiency but I have been using my nutrient schedule for a while now and the dont show deficiency. I turned the potency of the bigger light to 50% dimmed like 3 days ago, plus I double the dose of nutrients this week to see how they respond. Let me know what you think this yellowing and spots are.
@Lou_Grows, You're right. It was heat stress, I was pushing the plants as much as I could with a high light DLI and Co2, got very good fast growth around 28/29'C but started seeing stress up around 31/32'C so had to dial it back to 28/29'C.
I run a perpetual grow, the younger plants loved the higher temps but late flower ones didn't handle it well. In the end I've found that 27/28'C with 50-55% RH and Co2 is the best compromise for all the plants at different stages.