Yellow leaves

Hello guys.

I have some problems and as much as I read everywhere it gets really confusing for me to determine what is the exact problem.

My problem is that some ( 4 out of 8 ) plants are turning their leaves light green to yellow. some leaves are completely yellow and have brown tips ( looks like rust even ).

I should be feeding them correctly. I use b'cuzz A + B. bloom stimulator according to their instructions which are :

3 ml of each A & B per liter and 1 ml of stimulator per liter.

b'cuzz A is n-p-k: 4-0-4
b'cuzz B is npk: 0-3-4

Usually i know yellowing can be caused from nitrogen deficiency but it's already inside the solution. Also they are in flowering stage so nitrogen shouldn't be needed so much from what I know.

My suspicions are:

Gnats: Sow just one gnat maybe long time ago but freaked out and put a gnat defender on top of soil. Right now havent seen any ,but maybe I have aphids.

Nutrition products that I use are not that good maybe ?

Don't think it is any type of cold/light/heat stress.

Don't think is overwatering ( leaves are not dropping - even the yellow ones ) although recently i started increasing the nutritions and was rewatering almost each day to try to fix the nutrition balance ( will stop for a while )

Was suspicious about a sulfur deficiency or a potassium or a phosphorus deficiency too but am not an expert and all the pictures I've seen don't look like my problems.

I use mineral water Aqua pura:

Calcium: 14
Magnesium : 3.5
Potassium: 2.5
Sodium: 12
Bicarbonate: 20
Chloride: 17
Sulphate: 14
Nitrate: 35
Dry residue at 180C: 135
Fluoride: < 0.1
Ph at source : 6.1

I saw a post stating to go there first regarding problems but all the pictures there are missing: maybe it's because I'm behing a vpn.

also really sorry that on some picture the hps is on ( also saw that ),but on some of them you can just see the burn. Took the pix yesterday and saw the post about that today, but I'm so desperate.

Thanks,

Can you get a ph and ppm reading on the water after it is in the plant?

I think you are using to much nutes, I never follow the directions, always less than what it says!

They want you to use more so you buy more, some strains cant handle the directions for the nutes!

Just my guess over ferted lol, use straight ph'd water for a few waterings, get a read on the water coming out of the plant!

Peace

Hi. and thanks for replying . I took a reading yesterday and and all of them were showing 6.9 ( which is a bit high in my oppinion , but not so devastative ). Will take another one 2day when the lights get on. Sometimes if the ph is getting high ( because of nutrients ) before feeding them I lower it with white vinegar which is Distilled Barley,Malt vinegar and 5% acidity. Will try clearing the nutrients with pure water as you suggest. Thanks again for spending time here and looking at my problems before NYE.

People I really need advice . Have "" second to put triple """EXPERTS""" around me but telling me all bullshit in my opinon ( like heat stress bollocks ).

Have two major problems and don't know how to proceed.

1. Yellowing continues to appear and have yellow leaves






brown tips burning.

2. Not sure what the ? is this : small spots all over the leaves. Can't see any buggers anywhere ( tried with a magnifier ) . also suspicious about aphids/gnats: