Canna PK 13 14

When do I start using canna PK 13/14 on 8 week flowering strain, and how long for?
Cherrs

never belive how many weeks they say, always bank on 10 weeks,

i start pk at week 4.5 start at the recomended 1.5ml per litre then each week drop the pk 0.5ml per litre so week 6 ul be on 1ml and week 7 on 0.5ml and week 8 nothing

i hear people start at week 2, starting at 0.5 and go up to 1.5 per week then bak down likei just describednever
tried that method, seems the week 5 start works best.

Thanks, so if I'm watering twice a week would I water 1.5ml per litre twice in week 4.5, or once with pk and the second watering with canna flowers?

Anyone?.....................