Yellow Peril revisited

Below are the specifics of a problem I posted a few days ago. This time however I have laidit out by incorporating stinkys' form in a bid to aid clarity. Hope it assists in some sort of definitive diagnosis.

H=Answer if you grow hydro or aero N/A
C=Answer if you grow coco N/A
S=Answer if you grow traditional soil N/A
L=Answer if you grow soilless other than coco (Promix, Hyponex, SunshineMix)- Canna Terra Professional
R=Answer if you grow in RockWool N/A
T=Answer if you grow in HydroTon
D=Answer if you run any type of automatic drip system, including into soil or soilless N/A
E= EVERYONE needs to answer lol!

E-indoor or outdoor- Indoor
E-soil, soilless, coco, aero, or hydroponic- Soilless Mix
E-specific medium-
CSL-Soil type/brand- Canna Terra mix
HCL-Hydro/aero/soilless system type-Pot
SCL-Anything you have added to the soil- 10% Perlite
SCLR-Soil or slab runoff pH 6.5-7.5
E-Water source- Tap via Brita Filter
E-Source water pH 5.8- 6.0
HRT-Source water EC (if hydro)
E-Age of plant 8 weeks- 6 weeks grow, 2 weeks flower
E-Type of fertilizer- Hesi Soil TNT Complex, Canna SuperVit, Canna Cannazym in growth. In flower Hesi TNT & Cannazym stopped but Guerilla Grow Bud Added.
E-Rate of application- Hesi TNT @ 5ml/l,Supervit @ 0.1ml/l Cannazym @ 2.5 ml/l. Guerilla Grow Bud 3.5 ml/l
E-Lighting source and distance from plant 1 X 200W Blue (Grow) then 2 X 125W Envirolite Red (Bloom) 150-200mm from top of plant. water every 3rd day, 60 mins before lights out, until runoff observed. Flushed 3 days ago with 5l MgSo solution (1 level tsp) following initial advice..
E-Air temperature (both day and night if you are running a dark period) 19C Night / 27C Day
HD-Reservoir temperature N/A
E-Air % Relative humidity varies between 45% and 65%
E-Lighting schedule 12/12
E-Type of ventilation your room has. forced extraction through carbon filter
TR-Did you pre-soak your media in pH corrected solution? yes, pH 6 + 2.5 ml/l Rhizotonic

I should just add that this yellowing occurred on my previous grow and was never eradicated. eventually the leaves take on a translucent appearance and become plastic rather than crispy. It also seems to affect growing tips all over the plant, rather than just those in proximity to the light source, and seems to begin at the base of a healthy green leaf before slowly creeping to the tip.. I even changed medium from Plagron to Canna in an attempt to isolate the problem, without success. The grow before this was using bog standard supermarket compost and it went perfectly so what exactly can i be doing wrong? thanks.