Yellowing on smaller top leaves?

Hey guys,

Just curious on what you guys think could have caused yellowing around the edges of leaves on these ladies. These are about week 5 on a 10 week strain, I think I hit them with too much PK boost (crystal burst + snow storm) on top of their base which is canna. Should I flush until run off is low PPMs? Or should I continue feeding normal? They are in coco

They look fine now I would wait for any signs of burn to show before flushing, You might find its strain related good luck
Very nice work