Potassium Defiency? Day 42

[Littylovesdapiff]

-Problem: I have 4 plants at day 42, 3 of the 4 are getting browning along the edges of leaves and some tips on just one plant burnt, one more advanced that others. Is this potassium def? If so what is a good simple banana tea recipe? Im about 2 days or less from watering and would to prepare if possible for the fix. Runoffs are all around 1000 ppm and 5.8 on one plant is the lowest runoff ph of the bunch. If i missed any important info pls let me know i want to get a handle on this situation. THANKS
-Medium/grow method: 50/50 ff ocean forest/ happyfrog with 20% perlite 5 gal fabric pot
-Feed and supplements used: only fed twice ff trio at 1/8 strength 320 ppm and then 3/8 strength at 380 ppm a week and change apart. Feeding only water and tps 0% nitrogen calmag before then. Feed between 6.2 and 6.5 ph
-Water source: Rain water with ppm of 0
-Strain and age mephisto samsquanchog x forum stomper and barney farms purple punch all day 42
-Climate: 73-76 degrees F day and night 58-63%
- Light used MH FCE-3000 @ 14in away from canopy at 90%

 

[namvet25]

Move light up to 18 to 20 inches, 24 14in is a little close,Start feeding bloom nutes along with cal/mag and see if this helps.