Potassium Deficiency - or ?

I think have a Potassium lockout or deficiency.
Problem started on older leafs and have moved up to newer growth.
One pheno showing more signs than the other 2.
Could it be something els?
What can I do in this case with what I have on hand?

Substrate - Cococoir/perlite
Pot size - 10l
Irrigation - tray2grow
Nutrient - RO water, greenhouse powder feeding short flower (0,7g/l), Calcium (1g/l), Boost (0,3g/l) - EC1,6/ph5,8 - following the schedule and the profile looks like this.

Yeah you've definitely got a nutrient deficiency going on there

Its generally recommended by autopot (least it used to be)
That you run considerably less EC than a drain to waste method to avoid salt build up.

I'd be running it 1.2EC and I'd guess by the timing you have a build up of salts causing lockout

I'd lift a pot and do a top feed to check run off and I'd guess it's going to be a lot higher than you're putting in.

Like other people suggested you need to lower feeding strength if you only water/feed from the bottom. Lower feeding strength and feed more often solves most problems.

Looks like nutrient excess. You have plenty of K in that plant food. Never let the top surface dry out.

Cheers!

Thank you all for the input.
I have lowered the EC to 1,2. 0,8g/l calcium , 0,4g/l short, 0,3g/l boost
Let's see if they will produce some buds this time.