There's an exploit with an infinite cycle of Phyto-Gro (and similarly, Rich Phyto-Gro):
1 Pulverized Charcoal, 1 Niter, 1 Slag makes 32 Phyto-Gro,
and Thermal Recycler uses the
2 Sawdust, 1 Niter, 1 Slag -> 8 Phyro-Gro
recipe to reverse it, so it gives 8 Sawdust, 4 Niter and 4 Slag.
8 Sawdust can be crafted, burned and pulverized again to 1 Pulverized Charcoal,
making this the infinite source of Niter, Slag and Phyto-Gro, and all tiers of scrap.

Fixed.