# Tankmark – Aquarium Water Log — Reef & planted water test log

> Reef & planted water test log (iPhone/iPad app by Crusadi LLC.)

- Source: https://appshunter.io/ios/app/tankmark-aquarium-water-log/id6813679037 (this page in markdown: same URL + `.md`)
- Developer: [Crusadi LLC](https://appshunter.io/developer/1896566977)
- Category: Utilities, Lifestyle
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 17.0 · 1 MB
- Languages: American English
- Released: 2026-09-29
- Data updated: 2026-10-07

## What is Tankmark?

Unlimited readings. No monthly cap. No subscription — one purchase and it's yours.
CSV in and out, so your log is never locked in an app.

Tankmark is a water-parameter notebook for aquarium keepers. Log a test in seconds, see the trend, get a reminder, export everything.

LOG IN SECONDS
One sheet, numeric keypad, your parameters in your order. Skip anything you didn't test. Date defaults to now.

YOUR BANDS, YOUR CALL
Set a target range per parameter — or don't. The chart shades your band and colours the latest value in or out of it. Tankmark never tells you your water is "safe" or "dangerous" and never calculates a dose. It's a notebook, not a verdict.

SEE THE TREND
Latest value and sparkline for every parameter. Tap for the full chart with 7, 30, 90-day and all-time ranges. Water changes, doses, filter changes and new livestock show as markers on the chart, so you can see what changed after what.

BUILT FOR YOUR TANK
Freshwater, planted, saltwater and reef presets. Temperature, pH, ammonia, nitrite, nitrate, KH, GH, TDS, salinity, alkalinity, calcium, magnesium, phosphate. °F or °C, ppm or mg/L, dKH or meq/L, SG or ppt — switch any time, history converts with you.

REMINDERS WITHOUT THE GUILT
Test every N days, water change every N days. A missed reminder costs nothing and says nothing.

YOUR DATA
Everything lives on your iPhone and, if you turn it on, in your own iCloud. No account, no sign-in, no server of ours, no ads. Export any tank or all tanks to CSV from the share sheet.

FREE, THEN PAY ONCE
Free: two tanks, the last 30 days, reminders and CSV export.
Tankmark Pro is one payment: unlimited tanks and history, every chart range, CSV import, all exports. No subscription exists.

Questions or a parameter you're missing? hello@crusadi.org

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Tankmark Pro | $12.99 | one-time |


## Is Tankmark safe?

Not enough ratings yet to assess Tankmark.

## Is Tankmark legit?

Tankmark – Aquarium Water Log appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for Tankmark is 65 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 3 releases)

### 1.2 — 2026-10-04

Settings takes problems as well as ideas, and can restore a purchase.

### 1.1 — 2026-09-29

The reading sheet now puts the parameters you have logged first; the rest wait under More. Every field and the chart settings button have VoiceOver labels. Settings has a box for ideas; it goes to one person.

### 1.0 — 2026-09-29

No release notes.

## More apps by Crusadi LLC

- [Crusadi](https://appshunter.io/ios/app/crusadi/id6794887812)
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- [Paced: Bible Reading Plan](https://appshunter.io/ios/app/paced-bible-reading-plan/id6813679327)
- [Mod Ledger – Car Build Log](https://appshunter.io/ios/app/mod-ledger-car-build-log/id6813679643)

All apps by Crusadi LLC: https://appshunter.io/developer/1896566977

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-07.*