Hey guys want some help with the tip brown off on a thew leafs (photo 1 and 2) I'm thinking potassium.what you guys reckon? And any tips or ideas of my room. My room made by me i use 50mm cool room panels for the room it is 100% air tight room with a water system that drains to waste with that drains out of the grow room to a sealed water catcher out side. I have 2led Quantum board 300w each .I no nothing about there Lighting chart,par??? And a 6 in intake and 6 in cabin filter onto a inline fan taking out I grow in coco using canna nutrients self water 3 times over 24h and 1min each time I clean and refill and feed the water tankevery 7 days witch I only use rain water water tanks gets 60l a fill room dose get hot sometime but nothing over 30° but it's brisbane it gets hot.I could also get my hummunity lower in flower but I can't use air-conditioning. Yeah about it .hopefully you good growers could help thanks