Privacy Policy
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.
Short version: Normal dashboard use collects no personal data — tank profiles save under an anonymous random ID only. If you subscribe to our newsletter, we store your name and email address to send you updates. If your aquarium shop signs up for AquaCalc for Business, we hold your business contact details to run that account (see section 2.5). If you create an optional My Tank account, we hold your email so you can save and sync your tank (section 2.6). You can unsubscribe or ask us to delete your data at any time. We never sell your data, never share it with third parties for their own purposes, and never use it for advertising.
1. Who we are
AquaCalc is built, managed and owned by SaneChoice, based in the United Kingdom. Our registered address is Moulsham Mill, Parkway, Chelmsford, CM2 7PX.
For the purposes of UK data protection law, SaneChoice is 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.
2. What data we collect and why
2.1 My Tank usage — anonymous profiles, no personal data
When you use the AquaCalc dashboard (pH Monitor, RO Mixer, Dosing & Water Change tabs), your tank profiles and settings are saved to our server. They are identified only by a randomly-generated anonymous client ID that is created in your browser the first time you use AquaCalc. This ID:
- Is a random string — it contains no personal information and cannot identify you
- Is never linked to your name, email address, IP address or any other identifier
- Is never shared with third parties
To make sure your profiles survive a browser cache clear, the client ID is stored in two places: your browser's localStorage and a functional cookie named aqph_cid that lasts 2 years. If localStorage is cleared, the cookie is used to restore the ID automatically so your profiles are not lost. This cookie contains only the random client ID — no personal data. See our Cookie Policy for full details.
All calculations (CO₂, RO mixing, dosing, water changes) are processed server-side. Only the specific numerical inputs you enter for each calculation are sent to the server — no profile data is included in calculation requests, and no calculation inputs are logged.
2.2 Newsletter and weather email subscriptions
If you choose to subscribe to the AquaCalc newsletter, the product-updates email (from the changelog page) or the weekly weather forecast email, we collect the following data. Weather subscribers have additional location fields (marked below).
Account notification emails. If you have a My Tank account you can also opt in to notification emails — weekly maintenance reminders, a monthly tank digest, and replies to your comments. These are sent to your verified account email, use only data you have already saved (your maintenance schedule, tank profile and comments), and are off by default. You can turn each one off in your account settings or via the one-click unsubscribe link in the email.
| Data | Why we collect it | Who it applies to | How long we keep it |
|---|---|---|---|
| First name | To personalise emails ("Hi Bradley") | All subscribers | Until you unsubscribe or request deletion |
| Email address | To send you emails | All subscribers | Until you unsubscribe or request deletion |
| Sign-up date & time | Subscription record-keeping | All subscribers | Until you unsubscribe or request deletion |
| Confirmation status | To record opt-in: via a double opt-in email link, or by an affirmative action while signed in to a verified account | All subscribers | Until you unsubscribe or request deletion |
| Unsubscribe token | A random string used to authenticate one-click unsubscribe | All subscribers | Until you unsubscribe or request deletion |
| Update categories | Which update types you asked for (new articles, plant profiles, tool updates) so we only email you about those | Product-updates subscribers only | Until you unsubscribe or request deletion |
| City name | To label your weekly forecast email ("Forecast for London") | Weather subscribers only | Until you unsubscribe from weather emails or request deletion |
| Geographic coordinates (latitude & longitude) | To fetch your local weather forecast from Open-Meteo each week | Weather subscribers only | Until you unsubscribe from weather emails or request deletion |
| IP address (hashed) | Rate-limiting sign-up attempts — cannot be reversed to identify you | All subscribers | Up to 1 hour |
How location data is used: If you subscribe to the weekly weather forecast, you select your nearest city using a search box powered by the Open-Meteo geocoding service. The city name and its coordinates are stored on our server and used solely to fetch your local 14-day aquarium heat risk forecast each week. Your coordinates are sent to Open-Meteo's API (open-meteo.com) once per week to retrieve the forecast — see section 7 for details. They are never used for any other purpose and are never shared with any other third party.
Double opt-in: We use a confirmed opt-in process. When you submit the subscribe form, you are sent a confirmation email containing a link. You will not receive any emails until you click that link. This protects both you and others from being subscribed without consent. If you are signed in to an AquaCalc account, your email address has already been verified (you sign in by clicking a one-time link sent to it), so turning the newsletter on from your account or a signed-in prompt is itself a confirmed, affirmative opt-in and no separate confirmation email is sent. You can unsubscribe at any time.
Unsubscribing: Every newsletter, weather forecast, and welcome email contains a one-click unsubscribe link. Clicking it removes your name, email, and any stored location data from our list immediately. You can also contact us via the feedback form to request deletion.
What we never do with your email or location:
- We never sell or share your email address or location data with any third party (except Open-Meteo receiving coordinates solely to return a weather forecast, as described above)
- We never use your data for advertising or pass it to advertisers
- We never add it to any list other than the AquaCalc newsletter and weather forecast service
- We only send emails directly relevant to AquaCalc content
2.3 Anonymous analytics
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.
2.4 Feedback form submissions
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 |
2.5 AquaCalc for Business (aquarium-shop accounts)
AquaCalc for Business is a separate service that lets aquarium shops embed our tools and articles on their own websites. If your shop registers for it, we collect the details you provide plus a small amount of service data. This applies only to business account holders — not to ordinary visitors or dashboard users.
| Data | Why we collect it | How long we keep it |
|---|---|---|
| Company / shop name | To identify and label your account and embed licence | While your account is active; removed on request after closure |
| Your name (contact) | So we can address you and manage the account | While your account is active; removed on request after closure |
| Work email address | To send your one-time sign-in link, service/account emails, support replies and (unless you opt out) an optional monthly usage digest | While your account is active; removed on request after closure |
| Website / domain | To lock your embed licence to your approved site(s) and verify you own them | While your account is active |
| Phone number (optional) | Only if you choose to provide it, to contact you about your account | While your account is active; removed on request |
| Support messages & plan requests | To handle your enquiries and any plan changes | While useful for support; deleted on request |
| Embed usage counts (per approved domain) | To show you usage in your portal and operate the service | Aggregated service data; not linked to your customers |
Sign-in: the portal is passwordless — you sign in with a one-time link sent to your work email. A strictly-necessary session cookie then keeps you logged in for that visit only (see the Cookie Policy). We do not store a portal password.
Monthly usage digest: we may send account holders one short email a month summarising your own embed activity (loads, most-used tool, product-link clicks and your public "search-ready" score). We rely on our legitimate interest in helping you get value from the service; it contains no customer data. Every digest has a one-click link to turn it off, and you can toggle it any time under Profile in your portal. Turning it off does not affect essential sign-in or account emails.
Your customers' data: the tools you embed do not collect your customers' personal data, and the "Site Insights" overview in your portal is built only from publicly available information (for example public domain rankings, WHOIS/RDAP and DNS records, and your site's public homepage) via third-party sources such as Cloudflare Radar. Full terms are in our Business Terms of Use.
Payment: business accounts are currently provided free of charge and we do not collect any payment or card data. If paid plans are introduced in future, payment would be handled by a payment provider and this policy updated to describe it.
2.6 My Tank accounts (optional)
Using AquaCalc's tools and dashboard needs no account and stays anonymous by default (section 2.1). You may optionally create a free My Tank account so you never lose your saved tank and can open it on any device. This is the only consumer feature that collects a personal identifier, and only if you choose it.
| Data | Why we collect it | How long we keep it |
|---|---|---|
| Email address | To send your passwordless one-time sign-in link, and as the way to recover your tank on a new device | Until you delete your account |
| Link to your anonymous tank id | So your existing saved tank data becomes reachable from any device you sign in on | Until you delete your account |
| Sign-in timestamps | Basic account security/housekeeping | Until you delete your account |
| Favourite articles | The guides and plant profiles you save (a list of article references only), so you can find them again from your account on any device | Until you remove them or delete your account |
| Maintenance schedules | Your saved maintenance tasks and dates per tank (water changes, dosing, filter cleaning and the like), so your routine and calendar follow you across devices | Until you remove them or delete your account |
Passwordless: we never set or store a password. Sign-in is by a one-time link emailed to you (single-use, expires in 15 minutes). You may optionally add an authenticator app as a backup way to sign in; if you do, we store its secret and one-time recovery-code hashes solely to verify your sign-ins. No marketing: your email is used only for sign-in links and essential account messages — never newsletters or ads unless you separately subscribe. Deletion: you can permanently delete your account yourself at any time from your account page. This immediately and irreversibly erases your email address, any authenticator setup and recovery codes, your saved favourites, your maintenance schedules, and all the tank data saved on our server under the account (profiles, readings, dosing and RO settings) across every device. You can also ask us to do this via the feedback form. The same page lets you sign out of all other devices at once if you have signed in on a shared computer.
2.7 Article comments
You can leave a comment on our blog and plant articles. Comments are reviewed by us before they appear publicly. When you post one, we collect:
| Data | Why we collect it | Shown publicly? | Retention |
|---|---|---|---|
| Name (or nickname) | To attribute your comment | Yes — displayed with your comment | Until the comment is deleted |
| Comment text | To publish it once approved | Yes | Until deleted |
| Email address (optional) | To let you know when your comment is approved or if we reply, and — if it matches a registered My Tank account or a confirmed newsletter subscriber — to show a small “Member” or “Article Subscriber” badge on your comment | Never shown (the address itself is never displayed) | Until the comment is deleted |
| A one-way hash of your IP address | Spam prevention and abuse handling only | No | Until deleted |
You choose what to share: only a name and the comment are required; the email is optional. Do not include personal or sensitive information in a comment, as approved comments are public. We do not set any cookie to leave a comment. Removal: to have a comment (and its stored email) deleted, contact us via the feedback form. We moderate comments and may decline or remove any that are spam, abusive, off-topic or unlawful.
2.8 Shops map submissions
On the UK shops map you can suggest a shop or report a problem with a listing. Submissions are reviewed by us before anything changes on the map. When you submit one, we collect:
| Data | Why we collect it | Shown publicly? | Retention |
|---|---|---|---|
| Shop details you enter (name, type, location, website, notes) | To review and, if approved, add the listing to the map | Yes — once approved, the listing is public | Until removed |
| Report details (reason and any message) | To check and correct a listing | No — used only for moderation | Until resolved and cleared |
| Email address (optional) | Only so we can follow up if we need to check something | Never shown | Until the submission is cleared |
| A one-way hash of your IP address | Spam prevention and rate limiting only | No | Until cleared |
You choose what to share: the email is optional. Do not include personal or sensitive information, as an approved listing is public. We do not set any cookie to use the map. The "find shops near me" feature can optionally use your device's location (via your browser's location permission) to show the nearest shops — that location stays in your browser and is not sent to us. The map itself is drawn using tiles from OpenStreetMap, and typed place names are looked up via OpenStreetMap — see section 7.
3. Legal basis for processing
Under UK GDPR, we process data on the following bases:
| Data | Legal basis |
|---|---|
| My Tank profiles | Legitimate interests — providing the profile save/load feature you actively use |
| Newsletter subscription (name & email) | Consent — you sign up voluntarily and confirm via a double opt-in link, or by an affirmative action while signed in to a verified account; you may withdraw consent at any time by unsubscribing |
| Feedback form (message content) | Legitimate interests — improving AquaCalc based on user feedback |
| Feedback form (email, if provided) | Consent given at point of submission |
| AquaCalc for Business account data | Contract — to provide the business service you sign up for and take steps prior to it; plus legitimate interests in operating and securing the service. Optional fields (e.g. phone) rely on consent. |
| My Tank account (email) | Consent — you voluntarily create an optional account to save and sync your tank; you may delete it at any time. |
| Article comments (name, comment, optional email) | Consent — given when you voluntarily submit a comment for publication; you can ask us to remove it at any time. The IP hash relies on our legitimate interest in preventing spam and abuse. |
4. How we store your data
Newsletter subscriber list — stored in a protected file on our web server (Plesk/Apache, United Kingdom). This file:
- Is not publicly accessible — protected by server configuration
- Is accessible only to the site operator
- Is never shared with any third party
- Is transmitted by email only via our own SMTP server (no third-party email marketing platforms)
Tank profiles — stored in a protected directory on our server, indexed only by your anonymous client ID. This data contains no personal information.
AquaCalc for Business account data — stored in a protected database on our web server (Plesk/Apache, United Kingdom), accessible only to the site operator. It is never sold and never shared with third parties for their own purposes.
My Tank account data — your email and the link to your anonymous tank id are stored in the same protected database on our web server (United Kingdom), accessible only to the site operator, never sold or shared.
Feedback submissions — stored in a protected CSV file on our server, accessible only to the site operator, not shared with any third party.
IP addresses — stored only as one-way SHA-256 hashes for rate-limiting purposes. The raw address is never stored and the hash cannot be reversed.
Email newsletters are sent directly from our own mail server ([email protected]) to your address. We do not use Mailchimp, SendGrid, or any other third-party email marketing service. Your email address is never passed to an external platform.
5. Data retention
| Data | Retention period |
|---|---|
| Newsletter subscriber name & email | Retained until you unsubscribe or request deletion, at which point it is removed promptly |
| Pending (unconfirmed) sign-ups | Removed after 48 hours if the confirmation link is not clicked |
| Tank profiles | Retained indefinitely — linked only to an anonymous ID, not to you personally |
| Feedback submissions | Retained while useful for product improvement; deleted on request |
| Hashed IP addresses (rate limiting) | Up to 1 hour |
| AquaCalc for Business account data | Retained while your account is active; removed promptly on request after the account is closed |
| My Tank account (email) | Retained until you delete your account, then removed |
6. Your rights under UK GDPR
You have the right to:
- Access — request a copy of any personal data we hold about you
- Rectification — ask us to correct inaccurate data
- Erasure — ask us to delete your personal data. For newsletter subscribers, every email contains a one-click unsubscribe link that removes your data immediately
- Restriction — ask us to restrict processing of your data
- Objection — object to processing based on legitimate interests
- Portability — receive your data in a portable format
- Withdraw consent — where processing is based on consent (newsletter subscription), you may withdraw it at any time with no adverse effect by clicking the unsubscribe link in any email
To exercise any of these rights, please use the feedback form or click the unsubscribe link in any newsletter email. 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.
7. Third-party services
| Service | Purpose | Data shared | Privacy policy |
|---|---|---|---|
| Plausible Analytics | Anonymous page view counting | No personal data | plausible.io/privacy |
| jsDelivr CDN (2FA QR code) | Loaded only when you set up two-factor login, to generate the QR code (charts are now served directly from AquaCalc) | IP address (standard CDN request) | jsdelivr.com |
| Open-Meteo (geocoding) | City name search when subscribing to weather emails — your typed query is sent to Open-Meteo to return a list of matching cities | City name search text (not linked to your email) | open-meteo.com/terms |
| Open-Meteo (weather forecast) | Fetching your weekly aquarium heat risk forecast — your stored coordinates are sent to Open-Meteo's API once per week when your forecast email is generated | Latitude and longitude (weather subscribers only; no name or email is sent) | open-meteo.com/terms |
| Cloudflare Radar & public records (Business "Site Insights") | Compiling the optional Site Insights overview for Business account holders from publicly available data about their own website | A business account holder's own public website domain (no personal or customer data) | cloudflare.com/privacypolicy |
| Anthropic ("Ask AquaCalc") | Generating an answer when you use the optional "Ask" search — the question you type is sent to Anthropic's Claude API, together with relevant extracts from our own public guides, so it can write a grounded reply | The text of your question only (no name, email or account is sent). Anthropic does not use API data to train its models. | anthropic.com/legal/privacy |
| OpenStreetMap (map tiles) | Drawing the base map on the UK shops map — when the map loads, your browser requests map image tiles directly from OpenStreetMap's servers, as with any interactive web map | IP address (standard tile request); no name, email or account is sent | osmfoundation.org |
| OpenStreetMap Nominatim (geocoding) | On the shops map — when you type a town or postcode to find shops near you, or to place a pin on the "Suggest a shop" form, your browser sends that text to OpenStreetMap's Nominatim service to turn it into a map location | The town/address text you type (not linked to your name or email) | osmfoundation.org |
We do not use any third-party email marketing platforms. Newsletters and weather forecast emails are sent directly from our own mail server. Your email address is never passed to any external service.
8. Cookies
AquaCalc uses no advertising or tracking cookies. For full details of what we do and don't use, see our Cookie Policy.
9. Children's privacy
AquaCalc is not directed at children under 13. We do not knowingly collect personal data from children. If you believe a child has subscribed to our newsletter without parental consent, please contact us via the feedback form and we will delete the data immediately.
10. Changes to this policy
We may update this policy from time to time. The date at the top of this page shows when it was last revised. If we make material changes — such as collecting new categories of personal data — we will notify existing newsletter subscribers by email before the changes take effect.