Estimative Index is the dominant high-tech planted-tank dosing protocol. Concept (Tom Barr): dose enough nutrients that no macro or micro is ever the limiting factor for plant growth. Skip testing - just dose to known excess + water-change away the buildup. Standard EI weekly schedule: 3x weekly KNO3 (nitrate), 3x weekly KH2PO4 (phosphate), 3x weekly K2SO4 (potassium), 3x weekly traces (CSM+B or Plantex). Macros (per 60 gal): 1/4 tsp KNO3 = 7.5 ppm NO3 boost. 1/16 tsp KH2PO4 = 1.3 ppm PO4. 1/8 tsp K2SO4 = 7.5 ppm K. Reset: 50% water change each Sunday clears accumulation. Benefits: rapid plant growth, no deficiency diagnostic, predictable pattern. Drawbacks: heavy water changes, ongoing fert dosing, requires CO2 + high light for plants to keep up. Alternatives: PPS-Pro (lean dosing), ADA (substrate-driven low-EI), low-tech (no ferts at all - low-light only).
Reviewed by the Fast Aquatics husbandry team · Updated May 2026
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