Tankbook: aquarium water log

About this app

What Tankbook does

Tankbook is the offline aquarium chemistry logbook for the 14.7 million US fishkeeping households. Built for the reef keeper who tests calcium, alkalinity, magnesium, nitrate, phosphate, salinity, and pH every week — and for the freshwater planted-tank owner whose parameters matter just as much. What ships in v1: — Ten-second entry sheet. The parameters you actually test, big number pads, swipe through. Done in under a minute, even with wet hands. — Trend charts per parameter. Swift Charts line graph for every value, last 7/30/90/365 days. Spot a slow alkalinity slide before it crashes a coral. — Multiple tanks. Reef display, freshwater planted, quarantine, frag tank. Each has its own parameters and its own history. — Test-kit reminders. Calcium every Tuesday. Alk every Friday. EventKit notification local to this device. — OCR for color cards (Vision). Snap a photo of an API test card or refractometer scale, Tankbook reads the value into the row. — PDF chemistry report. One-tap export to take to your local fish store or share with your reef-club mentor. — Equipment log. Skimmer, calcium reactor, dosing pumps — record when you last replaced media or carbon. — Livestock list. Per-tank fish + coral + invertebrate inventory with add date. — Stays on this phone. No account, no cloud, no analytics. Your tank, your data. — Free. The AquaticLog $25-a-year paywall on reminders ends here. For the reef keeper who's tired of the AquaPlanner data-loss horror stories, the Aquarimate UI from 2012, and the AquaticLog subscription gate.