Aqua Plant Journal

Aqua Plant Journal is a water-chemistry logbook built specifically for planted freshwater aquariums. Test your water, log the numbers, and finally see what's actually happening in your tank over time — instead of guessing.

WHAT YOU CAN TRACK
• Nitrate (NO3), phosphate (PO4), KH, GH, pH, iron and temperature
• CO2 is estimated automatically from your KH and pH readings
• Full history for every aquarium you keep

TREND CHARTS
Overlay up to three parameters on one chart and watch how your water actually moves week to week — each line keeps its own real range, so a KH reading and a NO3 reading are never confused for the same scale.

EI DOSING CALCULATOR
Enter your tank volume and weekly nutrient targets, and get the exact weekly dry-dose in grams for KNO3, KH2PO4, K2SO4 and a trace mix. A built-in guide explains how and why the Estimative Index method works, right from the calculator.

MAINTENANCE & REMINDERS
Log water changes, fertilizer doses, pruning and filter cleaning. Set recurring reminders per aquarium, and snooze or mark them done with one tap.

BUILT-IN GUIDANCE
Every parameter comes with a plain-language explainer and the range most planted tanks aim for. Stray outside it and you'll get a gentle, non-blocking note — never a red error, always a suggestion.

PRIVATE BY DESIGN
No account, no login, no server. Everything you log stays on your device.

FREE TO START
Your first aquarium gets every feature for free, forever — parameters, trends, EI dosing, reminders, all included. A single one-time purchase unlocks unlimited aquariums and removes ads. No subscription, ever.

Available in English, Portuguese (Portugal), Portuguese (Brazil) and Spanish — Aqua Plant Journal follows your device's language automatically, or you can pick one manually in Settings.