Comparison

Reef Book vs Reef Guard

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Reef Book

Features
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Smart Logbook for Aquarists Record a water test in seconds, see whether each reading is in range, and follow how your aquarium changes over time. Reef Book keeps every aquarium’s history together across iPhone, iPad, and Mac. Set up each reef, planted tank, freshwater aquarium, or other aquatic system with the parameters you test, the units you use, and the ranges you want to maintain. Record Without Friction • Open Quick Record from the app, a widget, or a Shortcut • Type an exact value or adjust it with a precision slider • Keep repeated tests as separate readings instead of losing the individual results • Mark frequently tested parameters as favorites for quicker access Understand Your Results • See which readings are within range and which need attention • Follow changes across recent results or your complete history • Use the activity heatmap to see when you tested and spot gaps • Compare supported conversions directly from a logged reading • Add notes and suggested tags for maintenance, dosing, livestock changes, and other events Share and Stay in Sync • Invite other aquarists to view or contribute to the same logbook • Create a shareable summary, preview it, and choose what to include • Keep every device up to date through iCloud • Schedule automatic backups and choose how many to keep • Use Reef Book without creating another account Plus fun iMessage stickers!

About

Reef Guard

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Reef Guard – Simplify Marine Tank Care Take the stress out of marine aquarium management with Reef Guard, the all-in-one app designed to help hobbyists keep their tanks organized and thriving. Whether you have a small nano reef or a full-sized marine setup, this app focuses on the essentials: tank details, fish and coral tracking, equipment and supplies, and maintenance reminders. Tank Management Record and organize key information for your aquarium, including water volume, lighting, temperature, and setup notes. Keep a clear overview of each tank so you always know its status at a glance. Fish & Coral Tracker Log details for every fish, coral, or invertebrate. Track species, arrival dates, and care notes to maintain a complete record of your tank inhabitants. Build a digital overview of your reef community and monitor its growth and changes over time. Equipment & Supplies Manage all the gear that keeps your tank running smoothly. Log filters, pumps, lights, heaters, and other equipment, along with maintenance cycles and notes. Track consumables like test kits, salt, and filter media with stock levels and expiration dates, and set reminders so you never forget to restock or replace items. Maintenance & Reminders Create custom schedules for daily, weekly, or monthly tasks. Set reminders for water changes, equipment cleaning, and other routine maintenance. Mark tasks as in progress or completed to stay organized and keep your tank in optimal condition. Features at a Glance Manual logging for all tank data and inhabitants Track multiple tanks and their setups Detailed fish and coral profiles Equipment and consumable management Customizable maintenance schedules and reminders Intuitive, clean, and easy-to-use interface Stop relying on memory or scattered notes. Reef Guard keeps your marine tank organized, making it easier to provide consistent care for your fish and corals. Spend less time managing tasks and more time enjoying the beauty of your underwater world. Download Reef Guard today and simplify your marine aquarium care! Terms of Use:https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

Reef Book4 screens
Reef Guard4 screens

Verdict

The call

The clearest difference is price: Reef Guard at Free against Reef Book's $5.99. Reef Guard also leads on update cadence (fortnightly vs every 6 months) and iOS requirement (13.0 vs 26.0). Reef Book's advantage is in-app purchases (none vs 2). On ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Reef Guard is free to download; Reef Book costs $5.99 up front. Reef Guard sells 2 in-app purchases, starting at $1.99 per month. Reef Book asks for nothing beyond the download.

UpkeepUpdate frequency

Reef Book ships an update every 6 months, Reef Guard fortnightly. The most recent releases landed on September 18, 2026 and October 1, 2026 respectively.

Scorecard4 real differences · 2 level
Reef Book versus Reef Guard: the parameters behind the verdict, then further details
ParameterReef BookReef Guard
Price$5.99Free — better
Update frequencyEvery 6 monthsFortnightly — better
AdsNoNo
In-app purchasesNo — betterYes
DevicesiPhone, iPad, MaciPhone, iPad, iPod
Requires iOS26.013.0 — better
Further details — not scored
Size166 MB40 MB
Age rating4+4+
DeveloperReefSoft LLC宇 郭

In-app purchases

None

Reef Book

No in-app purchases

2 purchases

Reef Guard

Subscriptions2
  • Reef Guard Pro Monthly$1.991 Month
  • Reef Guard Pro Yearly$19.991 Year

Questions

Is Reef Book free?
Reef Book costs $5.99, with no in-app purchases.
Is Reef Guard free?
Reef Guard is free to download, with in-app purchases available.
Do Reef Book or Reef Guard have ads?
Neither Reef Book nor Reef Guard shows ads.
Which is updated more often, Reef Book or Reef Guard?
Reef Book ships an update every 6 months, and Reef Guard fortnightly. Most recently, Reef Book was updated on September 18, 2026 and Reef Guard on October 1, 2026.

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