HELP! Yellowing edges after flipping - hungry or overfed?

[babycthulu]

honestly can't tell if its a burn or she's hungry (this time round it is LSD from Barney's topped, lst and schwazzed)

this happens a lot with my grows, mostly every time i flip to 12/12. as with the pics, it is only at a certain stage/strata of growth
It looks like a cal/mag deficiency to me. Should I be bumping this up just before and during the 2 weeks after flip???
I add cal/mag at the suggested 1ml/l all the way through. Canna A+B + PK 13/14 as per canna's schedule

Coir in autopots (autopot.co.uk) using Canna A+B, Flairform CMX. pH @5.5-5.8 in veg, 5.8-6.4 in flower
Sunny crx 1500w (nominal - 270W measured draw) LED, 0.6x0.6x1.8m tent.
Air circ. Temp and RH always kept within the mighty Miss Nebula's guidelines. I'd be lost without this site and her tutorials...

 

[Mr.furley]

Hello babycthulu
This isn't a cal mag problem this is a potassium deficiency.
how do you feed your plants? Every watering? Every other watering?
Is that canna stuff that PH perfect crap?

Weed Pharma Cannabis puberty strikes again

 

[babycthulu]

awesome - thanks for responding
I feed them via a reservoir. The autopot is a gravity feed to a tray system (a float valve regulates the level in the tray) so it's kinda like a hydro system.
Just regular Canna a+b which i then have to pH adjust. I mix ~8l at a time and monitor it's pH
Nearly out of canna nutes, so will be trialing something else next round...

 

[Mr.furley]

I have seen those autopots but haven't used them, they look cool. Glad to help and good luck.