Ease of use, that's all.
If you want something that costs you 50cents per plant lifetime in fertilizer use hakaphos or kristalon, if you want something that costs you 5$ per plant use canna coco.
I would suggest Option D of the fertilizer combos I listed there. The only problem is the salts suck water out of the air. Once it has absorbed some moisture you can't accurately weigh it anymore. Storing it in a large container or bag will inevitably expose it to wet air so pre-package your ferts in small weighed portions you can just drop into your bucket/res later.
I didn't get any younger in the past few years and that's just too much of a hassle for me.