Soultion for bottom yellow leaves

[hector5.0]

Hello I have this auto I Don’t know the strain but she 60days old and now she is getting to bud more in flowering stage but i have too many lower yellow leaves some guy told me this nutrient burn so I decrease the nutrient does. The upper leaves the new ones are OK am just wondering what to do with it should i flash it little with plain water? Or keeping countine low does ? I already switched to bloom nuts I give them flora nutrients with 600 led lights 18/6 and bioa bizz mixed soil. The soil is big sometimes it takes 6 days to dry.