4 weeks into flower, extreme yellowing

Soil
Botanicare pro soil bloom nute
strain unknown
temp 75 degrees and humidity is 40-50
ph is 6.5-7

Fan leaves started yellowing and has progressed to the top. after they yellow they dry up and flake off. Thinking its lockout just not sure what steps to take, dont wanna make more problems. I did not get a chance to take pics of the plants but they look fine except for the yellowing progressing to the top which is starting to get severe, there arent very many fan leaves left!

Looks like nitrogen deficiency so im thinkin its nitrogen lockout since i have been feeding. will have pics up soon!
Any ideas on what could be done? Thanks

I would bring the ph down. Go for around 5.8~6.

pH sounds on point for soil, some strains just consume more N than others, can help this by addin some veg fert to ur bloom feed, assuming its a N def tho