Yup. Although I have heard eventually it will had aDsorbed so much that it no longer has the aBsorbing properties it did before.
I've never gonn more than 3 grows with one batch so I've never seen those diminishing effects.
Still needs buffering to proper ppm for what ever stage plant your using it for.
I've never thrown out coco.
Take as much of the roots out as I reasonably can and reuse. I do use a product like hydroguard to eat the left over roots.