Hi,
Im at the same stage as you and I use Coco Coir. Im now in second week and I add a bit of nutes at the end of week 1 so the EC is below 1.
I aslo use GHE Tri nutes and I add 0.5ml per liter of grow, micro, bloom and root booster 5ml per liter
Please see below website, there is chart, I hope that helps 😊👊👍
https://www.terraaquatica.com/wp-content/uploads/2022/01/TriPart.pdf