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Frequently asked questions
Quick answers about how Aquastat works, your data, and Pro.
What does Aquastat do?
You pick a tank type and log your water-test readings. Aquastat compares them against curated ideal ranges and tells you whether the tank is healthy, where the nitrogen cycle stands, and — for anything out of range — why it matters and how to fix it. It also charts each parameter over time.
Where do the ideal ranges come from?
Each tank type ships with curated reference ranges for the parameters that matter to it. The app only ever compares your readings against those ranges — it never invents numbers. You can also add your own custom parameters with Pro.
How does the cycle status work?
Aquastat looks at your ammonia, nitrite, and nitrate readings (and your tank's setup date) to estimate whether the nitrogen cycle is not started, cycling, or cycled, and whether it's safe for livestock yet. Log all three for the most accurate read.
Is the advice professional or veterinary advice?
No. Aquastat gives general, rule-based guidance to help you keep healthy water. It's informational only — you're responsible for the care of your animals. See the Terms of Use.
Does my data sync across devices?
Yes — if you're signed into iCloud, your tanks and readings sync privately across your iPhone, iPad, and Mac through Apple's CloudKit. You can also use the app entirely on one device.
Do you collect or sell my data?
No. Your data stays on your device and in your own private iCloud. We don't run servers that receive it, there are no analytics or ads, and we never sell or share anything. See the Privacy Policy.
Can I export my data?
Yes (with Pro). Export any tank as a single Markdown file — setup, parameters, health, and the full readings log — handy for pasting into an AI chat or sharing with a more experienced fishkeeper.
What's the difference between free and Pro?
Free covers up to 2 tanks with the full feature set. Pro unlocks unlimited tanks, custom parameters, and export — available as a one-time lifetime purchase or a monthly/yearly subscription, with Family Sharing supported.
I bought Pro but it isn't showing up
Open Settings → Restore purchases. Purchases are tied to your Apple ID; make sure you're signed in with the same one you bought it on.