I use the bricks, I look for the most natural ones that I can find. Cana Coco is probably the best I think, but it was out on Amazon last time I ordered a bunch, so I got another brand that worked really good and super easy to hydrate and break up:
Coco Mega Brick Premium Organic Plant Medium RHP Certified https://www.amazon.com/dp/B004T0G67S/ref=cm_sw_r_cp_apip_3WRO22oBNWKmN