Two Week old seedlings going yellow at base of leaves

OK so ive got some two week old sour kush seedlings going yellow at the base of the leaves. Also the texture of the leaves is kind of like crepe paper (like tissue) Also I have a younger one week old White Widow x Big Bud seedling showing similar issues but has brown blotches forming in the center of the leaves.

Im growing in coco. PHing my ph7.0 hard tap water to piss yellow ph6.0 with ph drops. For the last two feeds I have mixed 1.9 litres of water and add 1/4ml of A, 1/4ml of B, just under 4ml of Rhyzotonic, and about a quarter teaspoon of General Hydroponics PH down powder crystals. Leaving the solution for a day to check on ph before feeding. I last fed these seedlings on monday. Please help.

I was thinking it is Iron lockout maybe. Maybe because I have not watered them for 4 days and the PH has changed within the coco ? Should I just ph some tap water to 6.0 and flush them?

Ive got a nute solution as above in my previous post mixed up ready to go. Dont know whether to use it or flush them instead.

Hi Longtimetoker it's not soil it's coco coir.

OK so I gave them the feed last night, things look the same although I did catch the very first 5ml of runoff and it measured light green ph6.5. I have a pale of ph6.0 tap water standing by. I only fed these babies twice, could I be getting salt buildup already?

Im putting it down to lockout for now, but ill also give them a good flushing next watering tommorow because I think I can start to see salt buildup happening. The water board report says that our water is high Cal Mag so I dont think ill be needing to add suppliments.

Oh and last night I realised that my timer was set to override on 24/7, so it's kind of lucky I was up there so late. Will this have caused stress having 2 weeks of 24/0? I set it back to 18/6.

Thanks

Should I feed straight after flushing?

i always thought that the plants have enough energy in them to not feed them until they have some leafs. then start feeding them. i would be scared to burn them up.

They were loving it until the other day (they are still growing like they are on steroids though). I have only given them very small doses and think the issues are more due to ph than nutes. But they get a nice flush tomorrow so that should give them a nice cool drink. Also the older ones have been under light 24/7 and I only just realised this last night.

I dont know If I should feed straight after flushing out the salts, as coco is inert and has no nutrients in it. Im pretty sure they are big enough now to need some nutes, as the pots have been getting dryer quicker (which suggests to me that they are drinking now and developing a nice root system)

Hopefully if I have not got this all wrong there should be a pretty good 600w grow diary coming up. Im just finishing up my T5 Veg tent, then comes the ventillation system and then a nice digi 600w with adjustawing (possibly a scrog)

Cool thanks for the link. Trying to get around 5.8 with drops is hard. I have noticed there are 2 types of piss yellow though. One has a greeny surface layer of liquid and one has an orangey surface layer. You can kind of see which side of 6.0 the solution is when you first put the drops in.