First Time Coco Grow - Double Grape

First time growing in coco, so far so good. Started with canna coco bricks, hydrated and flushed them with PH 5.8 r/o water with about 200 PPM (1tsp/gal) worth of GH CALiMAGic. I germinated them in paper towel, then planted them directly into their final pots. One of them is currently growing in a hempy bucket with about 3 inches of perlite at the bottom. I live in a small country town and the hardware store only had one bucket left so the other is growing in a 3 gal fabric pot. After germination as soon as the first little serrated leaves started developing I added very low dose nutrients of around 100 PPM from the GH Flora Trio (300 PPM total at this point with the calmag). A few days later they were showing no signs of tip burn so I decided to up the does by another 100 PPM as I felt they could handle it.