Hey IGAG, i dont know what but for some reason P stands for phosphorus, with an f sound and K for potassium with a p sound... Looks like K deficiency, which is normal, the nute companies put loads of P and less K for some reason ,but with the full line up (very nice !) of nutes that you're using, you shouldn't have deficiencies like this. It's probably due to the Low PH you're having, you want to bring that up to 5.7 until 6.0 , this helps the plant process the nutrients. Hope this helps ! 🚀