Question about my feed

[My dixie normous]

Hi guys,
I switched to flowering 2nd April so i think im 4 weeks into flowering almost 5, You can see from the pictures they look good but the leafs lower (which i should trim) are dieing and falling off and the top have slight yellowing, I am using Canna Flora.
The strain is blue cheese I got as cuttings (i dont know if barneys or big buddhas)
the tank is between 40 - 50 ltrs

My main question is this... I just ordered 250ml of PK13-14 and I am not sure how to use or when.

Through Veg my plants didn't like EC going over 0.2 (without feeds my waters ec is 0.0)
I kept Ph at 5.8

Should I raise the Ec? or would they not like it still?

Thankyou for any feedback and the full diary can be viewed in the following link. https://www.thctalk.com/cannabis-foru...ro-grow!/page2

[My dixie normous]

No replys which means I am gonna have to go in this blind.

[Bud Lightyear]

Sorry mate think you Pm me about this, slipped through the net due to me being old and forgetful Anyway you can add your PK now mate @ 1/2 ml per litre and run it for 14 days that should give you a decent boost...

Regards BL