What would you recommend for safe toilet cleaning products?

As a general rule, the more natural the cleaning product the better.  Synthetic surfactants designed for toilet bowls for example, often contain chemicals, synthetic dyes, chlorine bleach, ammonia, petroleum-derived ingredients, and other harmful ingredients, such as Triclosan (prevents mold growth) that are incompatible and hazardous to a healthy bacterial eco-system living within your Fuji Clean system.  Ideal choices might include white vinegar, Borax, or other citric acid based cleaners.