Free EI (Estimative Index) fertilizer dosing calculator for planted aquariums. Enter tank volume + plant load, get exact teaspoons of KNO3, KH2PO4, K2SO4, and CSM+B per dose.
EI (Estimative Index) dosing oversupplies macro + micro nutrients to ensure plants are never limited, then resets via 50% weekly water change. Doses are scheduled 3x per week (Mon/Wed/Fri for macros; Tue/Thu/Sat for micros).
Standard reference: Tom Barr\'s Barr Report + Estimative Index thread on Plantedtank.net.
Browse the full calculator library for tank stocking, water change, dosing, PAR, electricity cost, heater sizing, CO2 BPS, salt mix, and more.
Whatever specific topic brought you here, four fundamentals govern long-term aquarium success: water quality, parameter stability, biological filtration, and species-appropriate husbandry. Skip any one and the others struggle to compensate.
Water quality: ammonia + nitrite at zero, nitrate under 30 ppm freshwater + 10 ppm reef. Test weekly with API or Salifert kits. Use our water parameter checker to score your readings against your tank type.
Parameter stability: stable wrong parameters beat fluctuating ideal parameters. Most fish tolerate a wide pH range if it's stable. Sudden swings of 0.4+ pH or 5+°F kill fish faster than chronic suboptimal values. Use temperature controllers (Inkbird) + automated dosing for consistency.
Biological filtration: the bacterial colony on your filter media + rock + substrate is the engine. Never replace all media at once. Use our filter turnover calculator to size correctly.
Species-appropriate husbandry: research adult size, territoriality, diet, and tankmate compatibility before purchase. Use our tank stocking calculator + compatibility guides.
How long does an aquarium take to set up? 4-6 weeks for full cycling + first stocking. Use our cycle ETA calculator + how long does cycling take.
What's the best aquarium for beginners? 20-gallon long. Big enough for parameter stability, small enough for budget + space. See beginner picks.
How often should I do water changes? 25-30% weekly. See water change frequency Q&A + water change calculator.
Why does my fish keep dying? 5 leading causes: uncycled tank, wrong species pairings, no quarantine, undersized tank, neglected water-change schedule. See full diagnosis.
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