Good advice by dave505 regarding raw garlic, turmeric and coconut oil.
I believe those affect less friendly flora than Colloidal Silver .
Even though I don't like to recommend supplements and prefer to rely on herbs and foods, I'd say supplementing with betaine HCL during meals is key in keeping the upper small intestine sterile. Lack of stomach acid is almost always present in something like SIBO.
Some homemade goat kefir would be beneficial, especially if you suspect candida issues. I don't quite believe the theory that pathogens feed on friendly bacteria. Kefir is actually a proven antiparasitic and antifungal drink.