AquaCalc is built with privacy as a core principle — not an afterthought. This policy explains what data we collect, why, and how it is protected.
Last updated: 17 June 2026 · Applies to: aquacalc.io and all subdomains
Short version: Your tank data, pH readings and water chemistry profiles never leave your device — they are stored only in your browser's localStorage. We collect no personal data during normal use of the dashboard. The only personal data we may hold is what you voluntarily submit via the feedback form.
AquaCalc is operated as a personal project based in the United Kingdom. For the purposes of UK data protection law, we are the data controller for any personal data collected through this website.
If you have any questions about this policy or your data, please use the feedback form.
When you use the AquaCalc dashboard (pH Monitor, RO Mixer, Dosing & Water Change tabs), all data you enter — tank parameters, pH readings, water chemistry, profiles and settings — is stored exclusively in your browser's localStorage. This data:
Calculation requests are processed server-side (our PHP backend performs the maths), but only the numerical inputs you provide for that specific calculation are sent — no profile data, no identifying information.
We use Plausible Analytics, a privacy-friendly analytics service based in the EU. Plausible does not use cookies, does not collect personal data, does not track you across websites, and is fully compliant with UK GDPR, EU GDPR and PECR.
Plausible records only aggregate, anonymous page view data (page visited, country, device type, referrer). No individual user is identified or tracked. You can read Plausible's privacy policy at plausible.io/privacy.
If you choose to submit feedback, we collect:
| Field | Required | Purpose |
|---|---|---|
| Feedback type | Yes | To categorise and route your submission |
| Subject & message | Yes | The content of your feedback |
| Name | No | So we can address you if we follow up |
| Email address | No | To reply to you if relevant — never used for marketing |
| Tank setup | No | Context for bug reports |
| How you found us | No | Understanding where users come from |
| IP address (hashed) | Automatic | Rate limiting only — stored as a one-way hash, not the raw address |
Under UK GDPR, we process feedback form data on the basis of legitimate interests — specifically, improving AquaCalc based on user feedback. Where you provide an email address, processing is based on your consent given at the point of submission.
Feedback submissions are stored in a protected CSV file on our web server. This file:
Your IP address is stored only as a SHA-256 hash for rate-limiting purposes and cannot be reversed to identify you.
Feedback submissions are retained for as long as they are useful for improving the product, and reviewed periodically. If you wish your submission to be deleted, please contact us via the feedback form with your submission ID (shown after submitting) and we will remove it promptly.
You have the right to:
To exercise any of these rights, please use the feedback form. We will respond within 30 days.
You also have the right to lodge a complaint with the Information Commissioner's Office (ICO) at ico.org.uk.
| Service | Purpose | Data shared | Privacy policy |
|---|---|---|---|
| Plausible Analytics | Anonymous page view counting | No personal data | plausible.io/privacy |
| Cloudflare CDN (Chart.js) | Serving the Chart.js library | IP address (standard CDN request) | cloudflare.com |
AquaCalc uses no advertising or tracking cookies. For full details of what we do and don't use, see our Cookie Policy.
We may update this policy from time to time. The date at the top of this page shows when it was last revised. Continued use of AquaCalc after changes constitutes acceptance of the updated policy.