Your post said FFOF. Miracle Gro is a different substrate. I was going to call @cannabineer to help as he has used FFOF. You can succeed with Miracle Gro but you have to know when the soil has run out of preloaded nutrients and what nutrients it has run out of.Yeah it’s the one I transplanted to miracle gro actually.
If you choose to run Canna Coco again I'd be happy to help as that's all I have run for years.