@Nilam, I have heard about ...

@Nilam, I have heard about products such as bio-enzyme blends which are supposed to inhibit anaerobes. However, these additives (we're back to a chemical) are proprietary, and I have found it virtually impossible to obtain any objective, non-anecdotal evidence of efficacy. But in theory, there could be catalysts that make it difficult for anaerobes to thrive. Another option, but we're still looking at chemical addition, is to increase the pH using something such as MgOH. That would certainly help control formation.