Reef: Aquarium Chemistry
Two-Part Dosing Calculator
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Saltwater chemistry that pairs calcium and alkalinity the way the chemistry works. Magnesium-first guidance, daily-rise caps, dose history. No subscription.
Reef is a chemistry calculator for saltwater reef-keepers. Log a test, get a dose. No accounts, no subscription, no ads.
The dose engine pairs calcium and alkalinity the way the chemistry actually works. When you dose calcium with a two-part product, you have to dose alkalinity alongside it in matched volumes — otherwise the ratio drifts and you end up chasing one parameter while the other crashes. Reef sizes both doses together against your tested gap, your tank volume, and the specific concentration of the product you use (BRS Pharma, Aquaforest, ESV B-ionic, Tropic Marin All-For-Reef, or a custom product).
Magnesium gets its own treatment. If your Mg sits below 1280 ppm, Reef tells you to fix that first — calcium and alkalinity won't stay in range without it. This is standard reef-keeping practice, but most calculators bury it.
Doses are capped to safe daily rises (about 20 ppm Ca, 1.4 dKH Alk) so you don't crash the tank reaching for a target in a single day. Larger gaps get split across multiple days, with the schedule laid out for dosing pumps.
Test history lives on a chart so you can see your alkalinity drift over weeks instead of guessing from memory. Dose history sits beside it so you can see what worked.
Everything stays on your device. Reef has no internet connection, no analytics, no accounts. Buy it once.
Built for mixed-reef, SPS, and LPS tanks.
Ratings & Reviews
Reef is now free to download. Try every feature free for 48 hours, then unlock forever with a one-time Reef Pro purchase — and anyone who already bought Reef keeps full access. Plus a refreshed app icon.
The developer, Roman Kopaliani, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Roman Kopaliani
- Size
- 980 KB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
English and 5 more
- English, French, German, Italian, Portuguese, Spanish
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Reef Pro (lifetime) $9.99
- Copyright
- © 2026 Roman Kopaliani