yellowing older leafs and purple on stems

Older leafs are turning yellow and stems from those leafs are turning purple. I thought it was caused by nitro def. so added more fertilizer but then got scared that i put to much so I flooded it n not sure what to do any more. any ideas?

No more.... U just burn your lady
flush with fresh water with correct ph (6.2-6.
3 times as soon as p
best wishes