A test kit gives you five numbers and a colour chart, and unless you write them down each test is an isolated reading with nothing to compare it to. Logged weekly, the same five numbers become a shape: nitrate climbing at a rate you can predict, ammonia flat at zero, the one week it was not. That is the difference between reacting to a dead fish and seeing the week before it.
7.1 pH · 0 mg/l Ammonia · 0 mg/l Nitrite · 22 mg/l Nitrate · 24.8 °C Temperature · No Water change
Sun 11 Oct
7.3 pH · 0 mg/l Ammonia · 0 mg/l Nitrite · 14 mg/l Nitrate · 25.2 °C Temperature · Yes Water change
Thu 8 Oct
7.2 pH · 0.3 mg/l Ammonia · 0.1 mg/l Nitrite · 30 mg/l Nitrate · 25 °C Temperature · No Water change
“Ammonia showing after rinsing the filter media under the tap. 50 % change and no feeding today.”
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What you’ll track
The Aquarium water tests log, out of the box
One entry per session, with the timer and location always available. Add or rename variables any time in log settings.
Variable
Type
Stats shown
pH
Number
Average
Ammonia · mg/l
Number
Max, Average
Nitrite · mg/l
Number
Max, Average
Nitrate · mg/l
Number
Average, Max
Temperature · °C
Number
Average
Water change
Yes / no
Count and share of yes
Timer
Built in
Total time, per entry duration
Location
Built in
Pin or place, shown on the log map
Notes, photos, sketches, voice memos
Built in
Attached to any entry
7.2
Average pH
0.3mg/l
Max Ammonia
0.0mg/l
Average Ammonia
0.1mg/l
Max Nitrite
How it works
From install to first entry in a minute
1
Pick “Aquarium water tests” during setup
The log is created with the variables above and a few example entries so you can see how it works. Clear them with one tap.
2
Log as you go
Tap plus, fill in what you have, save. Timer, location, notes and photos are there when you want them, hidden when you don’t.
3
Let the stats accumulate
Average ph sits on the log card, with the rest one tap away. Set a goal if you want a nudge.
Why this log
Built for the way you actually do it
The water change recorded with the reading that prompted it
One switch on the same entry as the numbers. Over two months the count and the percentage tell you how often you really changed water, which is almost always less often than the schedule in your head.
A weekly test goal with the streak in weeks
Set the goal to one test in seven days and the run counts weeks tested. That is the discipline that keeps a tank alive, and the only habit in fishkeeping worth putting a streak on.
Nitrate as a curve, not a colour
The average and the maximum over the log show how fast nitrate climbs in your tank with your stocking and your plants. Once you know it is nine or ten a week, the right water change interval stops being a forum opinion.
Everything else in the app
Not just a form. A logbook that thinks with you.
The Aquarium water tests log is one log among many you can keep. Every one of them gets the same tools.
💡AI analysis
AI reads the pattern for you
Tap the bulb on Aquarium water tests and get a plain-language read of your trends, what changed recently, and a suggested next goal, built only from your own entries.
🎯Goals
Goals, streaks and reminders
Set a target like three times a week, watch the rolling progress bar, keep a streak, and get a reminder at the time you actually log. The app learns that time from you.
📅Calendar
A calendar heatmap per log
Every log has its own month view showing which days you logged. Gaps are obvious, consistency is visible, and one tap opens that day's entries.
🔁Rounds
Several rounds in one entry
Every exercise in a workout, every piece in a practice session: logged together in one entry, broken out automatically in the stats.
📷Attachments
Photos, sketches, voice memos
Attach a photo, draw a quick sketch, or record a voice note on any entry. They stay with that entry and come back on every device you sign in on.
🗺️Map
Every entry on a map
Drop a pin or search for the place. Each log has a map view of everywhere you logged, and saved places open directly in Google Maps.
🔍Search
Search across everything
Find an entry by title, note or value across every log, filter by date or location, and jump straight to it.
🔒Privacy
Yours, offline first
Entries save on your phone first and sync when you sign in. No account needed to start, no feed, no one else sees your data.
Who keeps an aquarium log
People cycling a new tank, where the whole process is a sequence of readings and there is nothing to do but watch them move. Keepers of planted tanks who dose fertiliser and need to know what nitrate does between doses. And anyone who has lost fish and has no idea why, who wants the next unexplained death to come with three weeks of numbers in front of it.
It also suits people who go away. Leaving a written record for whoever is feeding the fish turns "the tank is fine" into something they can check, and the entry they add while you are away is the one you most want when you get back.
What two months of tests shows
Nitrate has a slope. In a stable tank it climbs at a rate that is nearly constant between water changes, and the log makes that rate obvious after three or four cycles of the routine. Once you know it, the water change schedule follows from arithmetic rather than habit, and you can see immediately when a new fish or a heavier feeding has changed it.
The exceptions are what the log is really for. A week where ammonia moves off zero has a cause — in the sample it was filter media rinsed under the tap, which killed the bacteria — and that cause is only findable because the reading and the note sit together. Everything here is your own record of your tank, not a diagnosis; when readings go badly wrong, the log is what you take to someone who knows the species.
Questions
Frequently asked
Which parameters should I actually test?
Ammonia, nitrite and nitrate answer almost every question in a freshwater tank; pH and temperature give them context. Add variables for KH, GH, phosphate or salinity if you keep a planted or marine tank — the log takes as many as you want.
How do I log a tank that is still cycling?
Test every day or two rather than weekly and the ammonia and nitrite spikes plot themselves. The moment both read zero with nitrate present is the end of the cycle, and it is far easier to see in a list than in memory.
Can I keep several tanks?
One log per tank, each tagged "aquarium". The overview groups them together while the readings, the averages and the water-change counts stay separate, which is how you notice that only one tank has the problem.
Should I add a photo?
Photographing the test tubes against the chart is the most useful habit here, because colour charts are read differently on different days. Attach the photo to the entry and you can settle any argument with yourself later.
