0 cm · The surface
The free aquarium logbook that forecasts your water parameters.
Every test, dose and water change in one place — and a trend line that knows your water-change rhythm, so you see the drift before the tank does.
Free. Ad-free. Yours. · Hosted in Germany · nothing to install
10 cm · How it works
Up and running in three steps.
Step 1
Add a tank
Name, litres, water type. reefnotes brings the matching target ranges along.
Step 2
Log your first test
Only what you actually measured. Empty fields are perfectly fine.
Step 3
Lean back
From the second reading on, the line is there. Stormy tells you where it's heading.
New to the hobby? A short tour takes you by the hand. Old hand? Just skip it.
25 cm · Inside
What it looks like inside.
The pages you open every day — no manual needed.
40 cm · The crew
Meet Manfred and Stormy.
Two zebra apple snails who live in your logbook. He's in no hurry, she misses nothing.
Manfred · the logbook
Remembers all the small details.
Every test, every dose, every water change — years of readings in one place. “Did I fertilise last Sunday?” Manfred knows.
- Top speed
- 0.003 km/h. He's in no hurry.
- Favourite value
- KH. It changes so pleasantly slowly.
- Never says
- “Eh, I’ll remember that.”
Stormy · the watcher
Notices the smallest changes.
When a value doesn't just spike once but really climbs, she gives you a small nudge — not loud, just early enough.
- Top speed
- For a snail: blistering.
- Favourite value
- NO₃. There's always something going on.
- Never says
- “It’s probably nothing.”
60 cm · Good to know
Free. Ad-free. Yours.
No limits
All your tanks, every test, every export. No pro tier, no trial that runs out.
Hosted in Germany
Export as JSON any time, deleted when you say so. Nothing is sold.
In the browser, everywhere
Phone at the tank, laptop at the desk — the same logbook, nothing to install.
Quick questions
All questions →Does reefnotes work for reef tanks, planted tanks and freshwater?
Yes. You pick the tank type when you create an aquarium — freshwater/planted, marine or reef — and the matching parameters and target bands follow. reefnotes grew up on planted freshwater tanks, so that's where the dosing logic has seen the most real data.
Can I use reefnotes on my phone?
Yes. reefnotes is a responsive web app that runs in any modern mobile browser. You can also add it to your home screen on iOS and Android via the browser's 'install / add to home screen' action.
Where is my data stored?
On reefnotes servers in Germany. No third-party analytics, no advertising trackers, no data resale; visits are counted by our own self-hosted, anonymous statistics without cookies. When you delete your account, everything you logged is removed by default; if you opt in at signup you can let your readings be kept fully anonymised (no name, no email, no tank names, no notes) so the trends and forecasts can keep getting better. See the privacy policy at reefnotes.com/en/privacy for the full list of what's logged and why.
Does reefnotes suggest doses?
Yes. Dose recommendations are tuned to your water-change cadence and the trend slope of the parameter you're correcting — so when NO3 is creeping up between water changes, you get a suggestion that closes the gap without overshooting.
80 cm · The substrate
Two snails and a fox.
My name really is Fuchs, German for fox. I keep a few tanks myself and never again wanted to wonder whether I dosed last Sunday. So I built reefnotes: a logbook without the forum, the paywall or the push storm. The snails do the work, I make the coffee.
Rafael Fuchs · a project by foxigit.com
Enough reading — dive in.
