Pythoff Plus maximizes the effective working life of water and nutrient, and helps prevent plumbing blockages (e.g. drippers, jets, filters, pumps). Pythoff is safe, non-toxic and non systemic: This enables dosing throughout the fruiting period, and compliance with 'organic' farming guidelines that prohibit the use of systemic chemicals. Safe to use from seed to harvest. Compatible with all systems and substrates. *Note: Pythoff Plus is not compatible with hydrogen peroxide or beneficial bacteria.