Old leaves turning yellow from outside.

Hey. So a week ago I posted that that two of my plants were showing this weird behavior of old leaves turning yellow from outside. Now almost all except the newly planted clones are showing the same problem.
I have been flushing them with pH-ed water (someone said it is zinc toxicity) but that doesnt seem to solve the problem.
The only feeding is either fishmeal/bone meal dusting I slightly mixed in the soil or the foliar spray of my planted tank water.
The soil is a mix of peat, coco coir, top soil, a teaspoon of fish meal and bone meal per sq ft, perlite and aged cow manure (not more than 5%).
I over fed the plants when they were young with NP heavy fert when they were young but havent done so since 3 weeks.

It looks like K def to me.

Doesnt coco coir has a lot of K?

how old is the plant and how big is the container? maybe the soil is just depleted, it looks hungry to me.

Plant's range from 60 days to 15 days. In 2 Liter pots.
The leaf is from a clone that had 9 days to root and 15 days in veg. Fed it once with fish meal/manure tea (1/6th diluted).
I have a fishmeal/bonemeal tea brewing since 8 days. 1tbp of each in 1 liter water. Will dilute it to 1/10th.
The leaf tips are brown/dead so I thought it might be some toxicity and didnt fed them (except foliar feeding).

tanan said:

Plant's range from 60 days to 15 days. In 2 Liter pots.
The leaf is from a clone that had 9 days to root and 15 days in veg. Fed it once with fish meal/manure tea (1/6th diluted).
I have a fishmeal/bonemeal tea brewing since 8 days. 1tbp of each in 1 liter water. Will dilute it to 1/10th.
The leaf tips are brown/dead so I thought it might be some toxicity and didnt fed them (except foliar feeding).

Click to expand...

Posting pics of the whole plant under regular lighting will help people help you. T

tanan said:

Hey. So a week ago I posted that that two of my plants were showing this weird behavior of old leaves turning yellow from outside. Now almost all except the newly planted clones are showing the same problem.
I have been flushing them with pH-ed water (someone said it is zinc toxicity) but that doesnt seem to solve the problem.
The only feeding is either fishmeal/bone meal dusting I slightly mixed in the soil or the foliar spray of my planted tank water.
The soil is a mix of peat, coco coir, top soil, a teaspoon of fish meal and bone meal per sq ft, perlite and aged cow manure (not more than 5%).
I over fed the plants when they were young with NP heavy fert when they were young but havent done so since 3 weeks.

Click to expand...

didyou find out what ur problem is becoz my plants look very much like urs do i have blood bone and fish meal in the soil to ???