Aquafern: Fish Tank Tracker

Tanks rarely fail suddenly. They drift.

Aquafern records a full set of water test results in about twenty seconds, then draws the line between them — which is where a slow drift actually becomes visible.

FAST ENOUGH THAT YOU'LL ACTUALLY DO IT

Most water logs get abandoned in week three, and it's nearly always for the same reason: entering six numbers took too long while you were stood over a tank with a wet test vial in one hand.

So Aquafern shows one parameter at a time on a full screen, with a keypad about twice the height of the keyboard's. The order and the positions hold, so the muscle memory carries from the first log to the thousandth.

Then the part that really saves time: ammonia, nitrite, nitrate and pH are read off a colour card that can only produce a fixed set of results — so Aquafern offers exactly those values as one-tap chips. No typing at all for most of a test. Probe-read parameters get a ladder around your last reading instead, because most barely move between tests.

CHARTS THAT ACTUALLY EXPLAIN SOMETHING

Every parameter gets its own chart on a shared timeline, with its ideal range shaded behind it. Readings outside that range change colour and pick up a marker, so nothing depends on you noticing a shade of green.

Your water changes are drawn straight through the whole stack. That's what turns "nitrate went down" into "nitrate went down because of Tuesday".

EIGHTEEN PARAMETERS, SIX TANK TYPES

Pick a tank type and Aquafern sets up the right parameters with the right targets — freshwater, planted, brackish, saltwater, reef or pond.

Ammonia · Nitrite · Nitrate · pH · KH · GH · Alkalinity · Calcium · Magnesium · Phosphate · Salinity · Temperature · TDS · ORP · CO2 · Iron · Potassium · Copper

Units convert both ways: dKH, meq/L or ppm CaCO3. Nitrate as the ion or as nitrogen. Specific gravity or ppt. Celsius or Fahrenheit. Values are stored once and converted for display, so switching units never rewrites your history.

Every target range is yours to change per tank, because a discus keeper and a Tanganyikan keeper don't agree about pH and both are right.

ALSO IN THE APP

• Water change and maintenance log, marked on every chart
• Dosing log, tracked against the parameter it moves
• Water change and test reminders, per tank, on your schedule
• CSV and PDF export — your data, anywhere you want it
• Multiple tanks, each with its own parameters and targets

NO ACCOUNT. NO ADS. NO SERVER.

There is nothing to sign up for. Your tanks and readings live on your device and back up to your own iCloud, so they survive a lost phone and appear on your iPad. We never see them — there's no server for them to go to.

No analytics, no advertising, no tracking, no email address.

FREE AND PRO

Free covers one tank, every parameter, fast logging, the maintenance log, and the last 30 days charted. Your data is backed up either way.

Aquafern Pro adds unlimited tanks, your complete history however far back it goes, reminders, CSV and PDF export, the dosing log, test kit expiry tracking, a photo on any reading, and the home screen widget. Target ranges, tank presets and CSV import are free.

Pro is $4.99/month or $29.99/year, with a 3-day free trial on the annual plan.

Aquafern is not veterinary advice. Target ranges are general hobby guidance and every one is editable — decisions about your livestock are yours.

Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/