Lavendar MOMMY QUESTIONS

[Yonkdiesel]

I have 3 KAv clones I put into a 5 gallon buckets together(lack of space) and have vegged then for about 9 weeks now they are gorgeous and lush green but just yesterday I noticed that there are some yello leave, They are all the largest fan leaves, not the newest grotwth but not the bottom branches either the yellowing starts at the tips and edges fothe defined serated leaf edges, and work back towards the stem fading back to green. I noticed each fan leaf with yello also has purple red coloring on the top side of the leaf sten. I used a rich soil mixture FFOX gaBat & seabird guano, leorandite and jumpstart fert ,with mychrozye and the top part of the containor is a coco/soil mix. I feed them every two or three days usually some b'cuzz grow aLaska fish emulsion and cal mag. I gave em alittle bit of AN's pirhana and tarntula, along with a bit of carbo load and some bloom nutes to add a little PK
anyone have any idea??? I keep the ppms pretty low around 400 or less at 6.6 ph so I'm not really sure although perhaps they got over fed accidentaly caue they got the bottom of the nute mix with all the chunks of guano and ferts any body recognize this? please help