Please help with this problem

Hello everyone. Hope all are well. Im having a problem and i am really getting annoyed. Im growing in coco. Ph 5.5 ec is 0.8 to 1.2. Temps are 24 to 26 degrees humidity 55. 5l smart pots. Doing a SOG style got 16 plants per 1.2 msq. They in 2.4m x 1.2. Under 2 1000w hps bulbs. Now i live in South Africa and my tap water is 0.1ec and. My ph is 9.1. But i adjust it once ive added the nutrients. The nutrients im using are the greenhouse seed company nutrients. We only get GHE 3 part and GHS nutes. So im not sure if this is nute burn or calmag def or toxidity or something but maybe someone can help me. Please see my pics of some of the leavea. View attachment 4141955 View attachment 4141955 View attachment 4141959

I make the calmag 0.3 to 0.4ec. And the other packet tops the ec up to 8 or 1.2. Is there something that i am doing wrong

Add a half cup of bleach per gallon, that will fix it.