What is the most important factor ,when growing in...

you cant really do soiless driving blind without a PPM meter, you'll need to start dosing your nutes and measuring input and runoff PPMs just so you can tell where you're at with any potential deficiencies or issues. Without that you'll be blind and run into problems for sure my friend. you'll need to switch to a coco appropriate regimen with coco A/B or NPKs for veg and flowering as well as a mix of micro preferably specialised so you get some "rare micro" and because the medium is "inert" you'll probably need a chelation agent like enzymes or humic and fluvik acid. Hope this helps get started right my friend ! 🚀