AquaCalculator 4+

aquarium app for aquarists


    • Free
    • Offers In-App Purchases


The reference software for dedicated marine aquarists

The AquaCalculator is not free. In order to be able to use the AquaCalculator permanently, you must complete a paid subscription after two weeks. In the first two weeks, the AquaCalculator can be tested for free and the subscription can be stopped at any time before it is chargeable.

The app for documentation and management of your aquarium. The main focus is on saltwater aquariums but also their freshwater pools can of course be documented with the AquaCalculator.
With the AquaCalculator you have the suitable manager at your fingertips to keep an eye on all important parameters regarding the care of your aquarium.

A big request: unfortunately we can not respond to reviews. If you have problems with the app, please contact us via email shortly (Support). So far we could clarify every question :-)

The reference software for every dedicated marine aquarist:

- Manage several basins in parallel

- Documentation of the water values ​​in graph and table form per pool. You can document your water readings, take notes or deposit pictures. The pictures can also be commented on.

- Animal Administration. You can also assign notes and pictures to your animals in the basin and thus get a quicker overview of the development of their stock.

- Dates: Management of recurrent memories help to keep track of the care of aquariums

- Realistic estimation of the required salt quantity of commercially available sea salt mixtures.
How much salt is actually needed to "adjust the salt content" or for the next "water change"? AquaCalculator calculates this using self-determined measurements of almost all commercially available sea salt mixtures.

- Addition of nutrients (nitrate and phosphate)

- Calculator to adjust calcium / alkalinity / magnesium: Expensive special agents are passé. AquaCalculator calculates the exact dosing quantities and stock solutions required for the adjustment of calcium, alkalinity (KH) and Mg concentration of low-cost salts.
Supports recipes from Aquafair, Aquaforest, Coral-Care, Fauna Marin, MT Aquaristics, Nyos, H.W. Balling, Price Aquaristics, A.Glaser, Red Sea, Sangokai, Tropic Marin, Fritz ProAquatics, Two Little Fishies, Kent Marine, Seachem, Brightwell, Continuum Aquatics, ESV and Self-Defined.

- Extensive setting options for the measuring instruments used, as well as the chem. Recipes.

- Mini-FAQ: answers the most important questions about adjusting the water values ​​and thus the successful care of reef aquariums. Including ten thousand times downloaded seawater FAQs by Martin Kuhn (Water Parameter FAQ, Anemone FAQ, Plague Master FAQs 1 and 2)

NOTE: We have provided iBooks from Apple for viewing the Seawater FAQs. The ad must have iBooks or another PDF viewing app installed on your device.

To use the AquaCalculator you must have a valid subscription.
This will enable you to take full advantage of the Aquacalculator, benefit from regular updates and enhancements, secure data storage and synchronization of your data with other devices.
Without a valid subscription, you can only read but not modify your data.
The term is one year.
Payment will be made through your iTunes account.
The subscription will automatically renew if it is not canceled 24 hours before the end of the current period.
Within 24 hours before the end of the current period, the amount for the renewal will be charged.
Termination of automatic renewal is possible at any time.

Terms of Use (EULA):
Terms of Use and Privacy:

What’s New

Version 2023.6.26

We are constantly working on minor and major improvements.
The aquarium care has been completely redesigned visually.
A few bugs have been fixed.

Ratings and Reviews

lengeta ,

Great app


jacob.lovett ,


$14 for a notepad?

Developer Response ,

I am sorry that you are not happy or not in need of the featureset of the AquaCalculator. But AquaCalculator is way way more than a notepad. Please refer to the Apps decryption or our website to get an overview of what AquaCalculator has to offer to ease you day to day routine as an aquarist.

App Privacy

The developer, Thallos, 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 Linked to You

The following data may be collected but it is not linked to your identity:

  • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Some in‑app purchases, including subscriptions, may be shareable with your family group when Family Sharing is enabled.

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