reefnotes
Your quiet aquarium logbook for the small daily rituals of the hobby.
For anyone keeping a tank, or just planning one. Every test, every dose, every water change in one place. Visualising your readings flags the slow drifts long before you notice them in the tank.
Free. Ad-free. Yours.
When the readings start to climb
The tank runs quietly in the background. When your readings start to wander — not just spike once — reefnotes helps. Together we spot the pattern before it becomes visible.
Groundhog Day, in the good way
Water changes, fertiliser doses, water tests — all in one place. What's due today? We'll show you. And if you can't be bothered, it's still there when you come back.
As private as a notebook
Free. No ads. No trackers. Your readings stay yours — not sold, not analysed for someone else, and always there for you.
Two snails looking into your tanks with you
Manfred has the calm of someone who has seen many water changes. Stormy is new, eager, and watching everything. They do not live in chat bubbles. They are simply there when you open the logbook — Manfred with patience, Stormy with wide eyes.
Manfred remembers all the small details of your tanks
Manfred remembers every test, every dose, every water change. Years of readings stay in one place, sorted by tank and parameter. When you wonder, “Did I fertilise last Sunday?” — Manfred has the answer.
Stormy notices the smallest changes
Stormy is eager, but watchful. She notices when your readings don't just spike once but really start climbing. When your pH or KH begins to rise, she gives you a small nudge — not loud, just early enough.
A long memory for a slow hobby.
Today on top. Tomorrow below.
Everything due across all your tanks today lands on one Today list — a water change here, a KH test there, fertiliser in the evening. The daily small stuff doesn't shout; it waits quietly in the monthly calendar just below. Forgot yesterday? Open the day, mark it done, skipped, or 'I'll get to it tomorrow.'
Your first tank? We'll walk you through it.
Manfred and Stormy meet you and your new tank with three small tasks: log a reading, set your tap water, find a rhythm. No clunky tutorials.
Every parameter, every tank, on one page.
Freshwater, reef, planted — same logbook, same cards. Each parameter shows the current value, its drift rate, and how long it's been in its target band. A glance, not a deep-dive — unless you want one.
The slow drifts, finally visible.
Water changes on a rule, monthly tests on cadence, fertiliser on Wednesdays at seven. Underneath: multi-month charts with water-change markers and a cycle forecast — so you can finally see whether the nitrate is really climbing, or it just looks that way on a Sunday morning.
Dosing that listens to your last water change.
The suggestions know what you just changed out, what your tap brings back, and what your last test said. Top up what's running low. Pause what's stacking up. Skip the math.
Same logbook. Beginner's pace, or pro's.
If this is your first tank, Manfred and Stormy walk you through the nitrogen cycle and what to test when. If you've kept tanks for years, skip the tour and drop straight into the data — every chart, every formula, every parameter, with the band edges and the rates you'd write down by hand.
Stormy is new here too.
You don't need a chemistry degree, and you don't need three forum threads either. Stormy is at her first tank as well — together you'll learn the nitrogen cycle, which numbers actually matter for fish, which ones for plants, and when the tank is safe to stock.
- An illustrated nitrogen-cycle guide, with 'when can I add fish?' as a real four-step checklist — not a gut feeling.
- A first-steps tour: one measurement, the tap-water profile, a water-change rhythm. That's all there is.
- When something drifts, Stormy spots it and Manfred says what to do. You don't decode a chart alone at midnight.
- Forecasts only appear when the data is honest enough. No numbers pulled out of a hat, no confident guesses.
Manfred has been at this a while.
A logbook serious enough to trust with a five-year reef. Every test, every dose, every water change across every tank you run — with formulas and units the way you'd write them on paper, and a multi-year trend chart that doesn't break when you scroll back.
- Multi-year trends per parameter, with confidence bands and water-change markers — same chart, last week or last decade.
- Per-product dose logs. Aqua Rebell® works out of the box; JBL® and others are coming. The app reads each product's recipe and turns a millilitre into a millimol on every parameter it touches.
- RRule recurring tasks, post-water-change dose triggers, and an honest 'I flipped the bottle' button for the days the math collapses.
- Pro mode renders the proper formulas — NO₃⁻, PO₄³⁻, K⁺, Ca²⁺, … — same UI, denser readout. The way you'd write it on a test-strip log.
From one aquarist to another.
I keep a few tanks myself, and I got tired of every aquarium app trying to be everything — a forum, a marketplace, a notification machine, a paywall. So I built what I actually wanted: a logbook anyone can understand. Water tests, doses, water changes, sorted by tank and parameter, with the effects underneath. No forum. No marketplace. No paywall. Free, ad-free, yours. If you keep a tank — or you're just curious — pull up a chair.
A personal side project of foxigit, reefnotes lives in the small daily rituals of the hobby — a water change here, a fertiliser dose there, a quick water test before bed.
Aqua Rebell® and JBL® are trademarks of their respective owners. reefnotes is an independent project — not affiliated with, endorsed by, or sponsored by these companies.