Know your water
before your plants do.
Aqua Plant Journal turns your weekly water test into trends you can actually read, EI dosing math you don't have to do by hand, and reminders so the next water change never sneaks up on you.
Coming soon to
iOS
Free for your first tank · No account needed · One-time upgrade for more · Android only for now
Log every parameter
NO3, PO4, KH, GH, pH, iron, temperature — with an estimated CO2 reading computed from KH and pH automatically.
See trends, not noise
Overlay up to three parameters on one chart and watch how they move week to week.
EI dosing, calculated
Enter your volume and weekly targets, get exact grams of KNO3, KH2PO4, K2SO4 and trace mix.
Reminders that stick
Water changes and dosing days, scheduled per tank — snooze or mark done in one tap.
Watch nutrients move, not just the numbers.
Three readings or thirty — pick up to three parameters and see exactly where your tank has been, with each series' real range shown alongside it so a KH line and a NO3 line never get mistaken for the same scale.
It's the difference between "my pH is 7.0" and knowing it's been slowly climbing for three weeks.
The Estimative Index method, done for you.
Type in your tank's volume and weekly nitrate, phosphate and potassium targets. The calculator gives you the exact weekly dry-dose in grams for KNO3, KH2PO4, K2SO4 and a trace mix — no spreadsheet required.
Want to understand why EI works the way it does? A built-in guide explains the method in plain language, right from the calculator.
Know why a number matters — not just what it is.
Every parameter field has a quick explainer: what it is, and the range most planted tanks aim for. Stray outside it, and a gentle, non-blocking note tells you why — never a red error, always a suggestion.
This is the part most tracking apps skip. Aqua Plant Journal is built to help you understand your water, not just record it.
Free is genuinely free — not a trial.
Your first aquarium gets every feature: parameters, trends, EI dosing, reminders. Nothing is locked behind a paywall. The upgrade only unlocks more tanks.
- 1 aquarium, full features
- All parameters & trend charts
- EI calculator & reminders
- Occasional ads
40% off — price goes back up to €4.99 soon.
- Unlimited aquariums
- No ads, ever
- No subscription, no recurring charge
- Pay once, keep forever
Your tank already keeps a log. Give it a good one.
Free to start, one tank, every feature. No account, no clutter. Available now for Android.
Coming soon to
iOS