Subcool soil. Potash? Or nute Burn?

Sup guys.

Going in on week 6 of flower and half my plants are going through some problems.
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Some leaves dont have burns on the edges. Some start in the middle of the leaf. And leaves effected are on top and middle of plant. Not the bottom ones.

I decided to go with subcool super soil since i had a bunch of leftover ingredients from like 2 years ago. Left it cooking for 2 months. August and October.

I veged with 600w MH and flowering with 1000w HPS. Using R.o water. Sometimes i add a bit of calmag and some epsom salt since i didnt added it to the super soil.
I did add a guano and casting tea along with molasses during week 2 of flower. But other than that, its just been R.O water.

Runoff is registering at 6.6 ph.

Strains affected. Dark Star and MK Ultra.

They are in 7-10 gallon pots. If its nute burn, FML. I really dont want to deal with flushing. Inreally hope its something else.

However, the other half is doing pretty well. My Pineapple Express #2 is doing pretty well. View attachment 3859997
However, i do see some yellowing on a couple middle leaves.

Heres the entire 5×5 closet.
View attachment 3860000

Top left and the 2 on the right are showing problems.

I really try to keep humidity up. Hence, the old wet clothes laying on the ground. I average 20% humidity with carbon filter on. When off, it ranges 40%.

If you need anymore info, please let me know.

Thank you all in advance for the tips and help.

Sammy.

I think the yellowing on PE is normal. Plants move nutes around especially late.
I don't know about the others but I don't think its a prob this late. Buds look great. Don't panic and don't flush.

Thank you for the reply.

I wasnt panicking until it kept getting worse and worse. Still got two weeks to go. Plus i still leave them for likr 5+ days in complete darkness. I appreciate your compliments.

Im afraid to add potash supplement in fear of accelerating the nute burn. If. It is. Nute burn.

Also. I dont see my pics on this post. Didnt realize that i posted twice. The post before this has thd pictures. Sorry.

looks like a K deff to me

but probably actually a cal/N and all round everything deff, a bit more all round feed or ph up better and slam them with some extra potassium sulphate next time

They`ll still finish fine

Personally I like to finish with just potassium sulphate for the last 7 to 20 days, sometimes just water for the last time to save myself some time and money....... but them bitches love potassium sulphate

Wow. Thanks for that great info. I dont have any pure potassium on hand but i added some Roots Organics flowering products just to add a little something. Better than nothing, eh? I also have some Buried Treasure guanos.

Not sure if i should use since it has high N and P but not much on K.

Was gonna use this recipe, but totally forgot all about it.

Flowering Nutrient Mix:
2/3 cup Peruvian Seabird Guano
2/3 cup if earth worm castings
2/3 cup High P guano (Indonesian or Jamaican)
5 tsp Maxicrop 1-0-4 powdered kelp extract
( that makes the dry mix make as much ad you want and save it for later)
Mix with water @ 2 cups per 5 gals.
To that tea add:
5 tbs of Liquid Karma
5 tbs Black Strap Molases
Use it EVERY watering

Not sure if i should do it EVERY watering for future reference.

As for the Potassium sulfate. Would an Espona brand work well? Any brands or products you recommend for K?

Thank yiu in advance

Your plants are over ferted. Why do you keep adding things when subcool's soil is designed to last the entire grow? Cooking it for two months probably made more fert available and maybe this is the real problem.