Dropwise: Fish Tank Water Test
Guided, timed, step by step
Free · In‑App Purchases
One payment. No subscription. No internet needed, ever. Dropwise runs your liquid test kit with you — the right order, one instruction at a time, and timers that overlap.
Dropwise runs your liquid test kit session with you.
Getting the number is the easy part. The fiddly part is everything before it: the tube, the drops, the shaking, the five minutes of waiting, and the sinking feeling that you have lost count at drop six.
Dropwise puts one instruction on screen at a time — fill to the 5 ml line, add eight drops from bottle one, cap and shake for five seconds — and holds the timers for you. When a test needs five minutes to develop, it starts that timer in the background and moves you straight to the next test, so a full round that would take twenty minutes one after another takes about seven. Each test tells you the moment it is ready, even with the device face-down on the worktop.
WHAT IT DOES
• Guided sessions for the kits people own — a five-test freshwater liquid kit, a six-test freshwater kit, and a GH & KH drop-count pair
• A kit builder for anything else — saltwater, pond, or a brand we have never seen: your tests, your drop counts, your waiting times, your scale values
• A drop counter with undo, for the tests where the count is the reading
• Overlapping timers with a tray, so the waiting collapses instead of stacking
• Numbers, not colour swatches — the printed scale that came with your kit is the only honest reference for colour, and the app says so on every reading
• A log of every reading, and hand-drawn trend charts that show the shape of a cycle across ammonia, nitrite and nitrate
• Target ranges you set yourself, per tank, from sensible starting points
• Cycle-stage reading, free-ammonia chemistry from pH and temperature, and dilution and volume calculators that show their working
• Reminders you set yourself
• Twelve plain-English articles: what each parameter actually is, the nitrogen cycle, and taking a reading you can trust
• Your maintenance log: water changes, filter cleans, livestock, anything
WHAT IT WILL NOT DO
Dropwise tells you what your numbers are — not what to do about them. It does not prescribe treatments, identify disease, or name products. It cannot see your tank, and decisions about your livestock should be yours.
FREE, AND PAID
Free forever: one tank, three complete guided sessions, manual logging, your full history, the trends, the insights and calculators, the articles — and the complete JSON backup and restore. Your readings are yours whether you pay or not.
One payment unlocks: unlimited guided sessions, unlimited tanks, the kit builder, reminders, custom parameters, CSV export of your readings, and export of your journal for any period. No subscription. Nothing further to pay.
PRIVATE BY DESIGN
No account. No analytics. No network connection of any kind — the app has no online mode to fall back on, because it has no server. Everything you enter is one file on your own device, and you can export it whenever you like.
Dropwise is independent. It is not affiliated with, endorsed by, sponsored by or connected to any test kit manufacturer. All product names and trademarks belong to their respective owners and are used only to describe which physical kits these procedures match.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Steadier guided tests, clearer kit names, and a set of fixes.
• The three built-in kits have new names that put the difference first: "Freshwater kit with high-range pH", "Six-test freshwater kit, KH and GH included" and "Hardness-only kit: KH and GH". A name you have given a kit yourself is kept.
• In the drop counter, the buttons stay where they are as the count changes, so a tap lands where you aimed.
• A finished timer's alert is marked Time Sensitive, so a Focus mode that allows Time Sensitive notifications lets it through.
• A reading that cannot be real is refused with a line saying why: below zero on a test that cannot go below zero, a pH outside 0 to 14, or a temperature outside −10 to 60 °C. Nothing you have already saved is changed.
• On iPad, a guided test's step sits beside its tips on more screen sizes, including iPad mini held upright, and the step fills the height of the screen. In an iPadOS 26 window, the back button no longer sits under the window's own controls.
• Several small buttons are bigger and easier to tap.
• On the smallest iPhones, the trend chart's legend fits above the tab bar.
• A new journal event is saved only when you tap Save. Leaving the form, or the app closing, no longer leaves a half-made one behind.
• Delete all data lists everything it will delete, and clears the app's backup copy at the same moment rather than at the next launch.
• If your device ever cannot save, the app says so on whatever screen you are on, and keeps your changes while it stays open.
• Restore a previous purchase says when it could not get an answer from the App Store, instead of saying no purchase was found.
• Smaller fixes to layout, wording and moving between screens with a keyboard.
The developer, Robert Deacock, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Robert Deacock
- Size
- 4.3 MB
- Category
- Utilities
- Compatibility
Requires iOS 16.0 or later.
- iPhone
Requires iOS 16.0 or later. - iPad
Requires iPadOS 16.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Unlimited guided tests & tanks $4.99
- Copyright
- © 2026 Rob Deacock
