T&C and Terms of Use of the ReefManager App

1. PURPOSE AND FUNCTIONALITY

Summary: The software is a supporting assistance system. The final decision and responsibility for all measures, especially when using AI, lies solely with the user. AI suggestions are experimental and can be faulty.

1.1 This software serves as a supporting assistance system for the operation and maintenance of saltwater aquariums.

1.2 It offers functions for calculating dosages, analyzing water values, and supporting aquaristic decision-making based on mathematical algorithms and, where applicable, AI-supported advice.

1.3 The author uses the software and associated hardware components on his own aquariums. Additionally, the software was extensively tested by a group of external testers in close exchange with the author before release. Although all known errors were fixed, undetected errors or unforeseen behavior (bugs) can never be completely ruled out, as with any complex software. The user is therefore required to check after every configuration or change whether it was applied correctly. Particular care is advised in parts of the app that are used less frequently and might therefore contain undetected errors.

1.4 All calculations, recommendations, and suggestions generated by the software are expressly to be understood as non-binding aids. The final decision and responsibility for the implementation of any measures lies solely with the user. This is not least an indispensable prerequisite, as the app assumes an idealized system.

1.5 Usage in extreme cases: The software is designed for typical use by hobby aquarists. Usage in extreme scenarios (e.g., managing a very high number of aquariums, entering an excessive amount of measurement data such as hundreds of ICP analyses) can push the app to its performance limits and lead to unforeseen behavior. Such use cases must only be carried out with special caution and ideally by experienced users or professionals who can critically monitor the results.

1.6 The integrated AI tool (e.g., based on Gemini API) is to be understood as an experimental assistance system. The generated answers and suggestions can be inaccurate, incomplete, misleading, or erroneous. The user acknowledges that AI systems make mistakes and can generate information that does not correspond to the current scientific state or proven aquaristic practices. The use of AI functions is at the sole risk of the user. The author assumes NO responsibility or liability for the correctness, usefulness, or applicability of the information generated by the AI tool. Any recommendation originating from the AI tool must be validated with the same or increased care and critical examination as any other software recommendation (see especially Sections 6 and 7).

2. THE CENTRAL ROLE OF INFO DIALOGS AND YOUR DUTY TO CHECK

Summary: You acknowledge that reading the info dialogs ('?') is a prerequisite for safe use. If a result is illogical to you or you do not understand it, you pledge not to apply it before seeking clarification. It is urgently recommended to contact the community or the author in case of uncertainties.

2.1 The Info Dialogs as an operating manual: The info dialogs distributed throughout the app (marked by animated '?' symbols) are the mandatory operating manual of the software. They explain in detail the functionality, the underlying logic, and the correct application of the respective function. The user pledges to read these explanations carefully and completely before using a function for the first time. As well as to read & understand them repeatedly if doubts arise regarding the handling of the function or the calculation.

2.2 Your indispensable duty to check: Reading these dialogs is mandatory to enable the user to independently check the results generated by the app (calculations, recommendations, AI answers) for plausibility. This check is the decisive step to compare the app's recommendations with one's own observations of the aquarium and to make a well-founded decision regarding their application.

2.3 Condition for use: Understanding and plausibility check: The user acknowledges and accepts that understanding the functionality explained in the info dialogs is a mandatory prerequisite for the safe application of the software. Should a result appear incomprehensible or implausible to the user, or should they not understand the explanations in the info dialog, they pledge not to apply the corresponding recommendation or function before seeking clarification. The application of a recommendation contrary to this obligation (i.e., in case of unclarity or doubt about plausibility) is done exclusively at the user's own and full risk.

2.4 Offer for clarification and your contribution to improvement: In case of uncertainties or implausible results, assistance is offered to the user. It is urgently recommended to contact the Community WhatsApp Group or the author directly (info@reefmanager.eu) for clarification. Your inquiry is not only important for your safety but also a decisive contribution to improving the software, as it can point out possible errors or edge cases. Direct links to these contact points can be found in various places in the app.

2.5 Experimental functions: Certain functions of the app, such as the automatic import of analyses from PDFs or the clipboard, may be explicitly marked as 'Experimental'. The user acknowledges that such functions may be incomplete, faulty, or unreliable. An increased duty of care and checking applies to the user for these functions. The author assumes no warranty for the correct function or the accuracy of data generated by experimental functions. Usage is at the sole and full risk of the user.

2.6 Liability for disregard: Liability of the author for damages arising from the disregard of this explicit duty to check and inquire (Points 2.1-2.5) is, as far as legally permissible, excluded.

3. COPYRIGHT AND PROPRIETARY RIGHTS

Summary: All rights to the software and algorithms belong to Christian Kitzel. Any unauthorized use, copy, or analysis of the algorithms is strictly prohibited.

3.1 All rights to this software, including, but not limited to, source code, design, user interface, graphics, texts, underlying algorithms, calculation logics, and associated documentation, lie exclusively with Christian Kitzel.

3.2 The algorithms and calculation logics implemented in this software are the intellectual property of the author. Any extraction, replication, analysis, use, or application of these algorithms outside of this app, whether for private or commercial purposes, as well as their sale, distribution, or publication in any form, is strictly prohibited without the express written permission of the author and constitutes a serious copyright infringement.

3.3 Any copy, modification, decompilation, reverse engineering, distribution, or other use of the source code or the compiled software/firmware without the express written permission of the author is strictly prohibited and constitutes a violation of copyright laws.

3.4 The app uses certain open-source components that are used under their respective licenses. A list of these components and their licenses can be provided upon request.

4. SYSTEMIC COMPLEXITY AND USER RESPONSIBILITY FOR DOSAGE RECOMMENDATIONS

Summary: Every aquarium is unique. Dosage recommendations are only suggestions. You MUST check every recommendation for plausibility BEFORE application. Do not apply any recommendation you do not understand. In case of problems, you are obligated to immediately take countermeasures (e.g., stop dosing, water change) to mitigate damage.

4.1 The software and its calculations are based on idealized models of a saltwater aquarium system. It is expressly pointed out that a 'perfect' or universally 'ideal' aquarium does not exist in reality.

4.2 Every aquarium is a unique biological system with individual parameters, inhabitants, and consumption rates. Dosage recommendations of the software must therefore always be adapted by the user to the specific conditions of their aquarium and critically evaluated.

4.3 Before EVERY adjustment or implementation of a dosage recommendation, the user is obligated to carefully check the visual condition of their aquarium, especially of the corals and other sensitive inhabitants. Changes in the behavior or appearance of the living creatures can be indicators that require an adjustment of the dosage (independent of pure water values) or make a recommended dosage appear inappropriate.

4.4 A saltwater aquarium is an extremely complex biological and chemical system. Control and assessment must never be based solely on measured water values. Visual assessment of the overall system, the behavior of the animals, and the growth of the corals is an indispensable part of aquarium care and must be considered in every decision regarding dosages.

4.5 ANY dosage recommendation of the software, whether through standard calculations or the AI tool, represents merely an aid and a suggestion. The user pledges EXPRESSLY to carefully check and validate every single dosage recommendation or adjustment before application for (a) its mathematical correctness (based on the values entered by the user and the software's algorithms) AND (b) its sensibleness and appropriateness with regard to the current visual and measured state of their specific aquarium. NO dosage recommendation may be applied by the user which they have not previously comprehensively checked for correctness and sensibleness and understood. The user is responsible for retracing the underlying calculations.

4.6 The user acknowledges that due to the countless different commercial products, their different formulations (bindings to stabilizers), and concentrations (quantitative), it is technically not possible for the software to check every dosage recommendation for plausibility. In particular, the software cannot validate the correctness of the data entered by the user (e.g., concentration of a product, change of increase values). Therefore, the responsibility for a basic plausibility check before EVERY application lies without exception with the user. This check includes in particular: checking the magnitude of the result (0.01ml, 0.1ml - 1ml, etc.), comparing it with the visual state of the aquarium, and ensuring that no dosage is carried out if the target value has already been reached or exceeded. Applying a dosage without this independent check is at the sole risk of the user. Regular measuring, especially at shorter intervals when approaching target values, is mandatorily required due to the instability prevailing in this phase.

4.7 The software is an assistance system. It does not replace the expertise, experience, careful observation skills, and judgment of the aquarist.

4.8 The user is obligated to critically check EVERY dosage recommendation of the software before application. The application of dosage recommendations or the preparation of mixtures is IMPERMISSIBLE if: (a) the measured values do not appear plausible, (b) the recommendation does not correspond to the current state of the aquarium, (c) the calculation bases are not comprehensible, (d) the recommendation contradicts visual observations, or (e) the user does not fully understand the recommendation. In case of doubt, dosing must be refrained from and professional advice sought.

4.9 Special duty of care with high-value stock: The user acknowledges that with the value of the animal stock, the potential risk of damage also increases. In aquariums with particularly rare or expensive stock, an increased duty of care and checking applies to the user. Recommendations of the software are to be evaluated with special caution in such cases and ideally secured by a gradual approach and additional control measurements. The final responsibility for the high risk remains fully with the user.

4.10 Duty to mitigate damage and take countermeasures: The user is obligated to continuously observe the condition of their aquarium. If they notice negative developments (e.g., discomfort of animals, unexpected measured values) that could indicate a faulty dosage or other issues, they are obligated to immediately take appropriate countermeasures to mitigate damage. This includes, in particular, immediately stopping the relevant dosage, intensive root cause analysis, performing water changes, and possibly consulting other experienced aquarists, professionals, the community group, or the author. Failure to observe these basic aquaristic duties of care is at the user's expense.

5. PROHIBITION OF COMMERCIAL USE

Summary: The license applies only to private use. Any form of commercial use (e.g., by retailers, breeders, maintenance services) is strictly prohibited without a separate written license.

5.1 The license granted to the user within the scope of the App Store entitles exclusively to private, non-commercial use of the software on the user's own aquariums.

5.2 Any commercial or business use is expressly prohibited. This includes in particular, but not exclusively: use in retail stores, in commercial breeding or holding facilities, as part of commercial aquarium maintenance services, or the resale of data and recommendations generated by the app.

5.3 Commercial use is only permitted after concluding a separate, written license agreement with the author. Interested parties are asked to contact the author directly.

6. THIRD-PARTY SERVICES & DATA

Summary: The app may use third-party services (Login, Firebase, AI). Their terms apply additionally. No liability for their data collection or availability. User is responsible for backups.

6.1 This app may use login services from Google and Apple. When used, the terms of use and privacy policies of the respective providers apply additionally.

6.2 This app may use Firebase for storing app settings, user data, and optional backups. Usage is subject to the terms and privacy policies of Google Firebase.

6.3 This app may use the Gemini API or similar AI services from Google or other providers for AI functions. Usage is subject to the corresponding terms and privacy policies of these providers.

6.4 The author assumes no responsibility or liability for the collection, processing, and storage of data by these third-party services. The user is required to inform themselves independently about the privacy practices of these providers.

6.5 The user is solely responsible for managing their data, including creating and safely storing backups, especially if these are done via Firebase or other cloud services. The author assumes no guarantee for the availability, integrity, or recoverability of data stored via third-party services.

6.6 DATA PROTECTION (General): This app collects NO cookies or tracking data to analyze user behavior. Neither cookies are stored nor passed on to third parties for advertising or analysis purposes. The app uses NO tracking. All aquaristic data (measurements, notes, etc.) remain exclusively on the user's device, unless a cloud function like backup or the community map is expressly used.

6.7 DATA PROTECTION (Cloud Functions): When using cloud functions (e.g., user account, backup, community map), the necessary data is stored on Google Firebase servers in the EU. This includes your email address for the account as well as the data you actively share for the backup or community map. The processing of this data is subject to the data protection regulations of Google Firebase. The author has no direct access to your passwords.

7. WARRANTY (LIABILITY FOR DEFECTS)

Summary: You are entitled to statutory warranty rights. In case of defects, the author will try to remedy them through updates. However, a deviation based on the uniqueness of your aquarium does not constitute a software defect.

7.1 The statutory warranty rights for digital products apply to this software. The software must correspond to the subjective and objective standard of suitability and quality that you as a user can reasonably expect.

7.2 A material defect does not exist in particular if the software is suitable for the purposes for which software of the same type is usually used and has a quality that is usual for software of the same type and which the user can expect. As described in Sections 1 and 4, every aquarium is a complex system. The software is a supporting aid; a guarantee for achieving certain biological or chemical results in an individual aquarium is not assumed.

7.3 If a defect occurs in the software, you as a user initially have a claim to supplementary performance (§ 327i BGB). The author will attempt to remedy the defect within a reasonable time and without significant inconvenience to you, usually by providing an update.

7.4 You can terminate the contract (and demand a refund of the purchase price or the last subscription fee) if (a) the author refuses supplementary performance, (b) the defect is so significant that immediate contract termination is justified, (c) an attempt at supplementary performance has failed, or (d) the author has declared that they do not want to or cannot remedy the defect.

7.5 Liability for defects is excluded for problems attributable to improper operation by the user, incompatible third-party hardware, or disruptions of third-party services (see Section 6), provided these are not the responsibility of the author.

8. LIABILITY AND USER CO-RESPONSIBILITY

Summary: Liability is limited to intent/gross negligence. Your co-responsibility is decisive: You must prove the cause of damages, and your duty to check and mitigate damage significantly limits or excludes the author's liability.

8.1 The author is liable without limitation for intent and gross negligence as well as for damages resulting from injury to life, body, or health.

8.2 In cases of slight negligence, the author is liable only for the breach of an essential contractual obligation (cardinal duty). An essential contractual obligation is an obligation whose fulfillment makes the proper execution of the contract possible in the first place and on whose observance the user may regularly rely.

8.3 The liability of the author is significantly influenced by the co-responsibility of the user. As extensively explained in Sections 1, 2, and 4, every aquarium is a complex, dynamic system. All recommendations of the app are therefore to be understood as non-binding suggestions, which the user must mandatorily check for plausibility and sensibleness for their individual system before every application. Damages attributable to the fact that the user does not comply with this indispensable duty to check do not fall to the author's expense.

8.4 The author is not liable for the availability, security, or correctness of services of third parties (e.g., Google Firebase, Gemini API, Apple Login). In particular, no liability is assumed for damages arising directly or indirectly from information, suggestions, or the behavior of the integrated AI functions. The use of these experimental functions is at the sole risk of the user and is subject to their unrestricted duty to check.

8.5 In the event of liability pursuant to Section 8.2, this is limited to the damage typically foreseeable at the time of the conclusion of the contract.

8.6 The above liability regulations also apply in favor of the author's vicarious agents. Further liability is excluded.

8.7 Burden of proof and interruption of the causal chain: In the event of damage, the full burden of proof lies with the user that (a) a defect in the software existed, (b) damage occurred, and (c) the defect was the direct cause of the damage. This proof of causality is considered not provided and the causal chain interrupted by the user in particular if the user has not complied with their own duty to check for plausibility as set out in Sections 2 and 4, and the result should have been recognized as faulty or implausible if appropriate aquaristic care had been applied. An obviously nonsensical result (e.g., an extreme over- or under-dosing) excludes liability of the author, as the damage is then no longer based on the software error but on the grossly negligent application decision of the user.

8.8 Duty to mitigate damages (§ 254 Para. 2 BGB): The author's liability is further limited by the fact that the user has a statutory and contractual duty to mitigate damages. If the user culpably fails to avert or mitigate the damage (in particular by taking the countermeasures mentioned in Section 4.10), their claim for damages may be reduced according to their share of contributory negligence or eliminated entirely.

8.9 Graduated responsibility in damage development: The user acknowledges that damages caused by software errors typically develop in two ways: (a) Extreme, obviously implausible miscalculations must be detected by the user's duty to check (Sections 2 and 4); liability for consequential damages is excluded here (see 8.7). (b) Subtle, not immediately recognizable as implausible miscalculations usually do not lead to immediate, catastrophic damage, but to a creeping deterioration of water values. The resulting consequential damage (e.g., loss of animals) only occurs if the user does not comply with their duty of observation and damage mitigation (Section 4.10). In this case, the typically foreseeable damage directly attributable to the software error is limited to the costs of restoring the original water quality (e.g., through water changes, use of absorbers). Liability for further consequential damages is excluded due to the user's failure to take countermeasures.

9. USE OF COMMUNITY FUNCTIONS & CONTENTS

Summary: Your profile data, images, and comments are visible to others. You guarantee that you own all rights to uploaded images. The author is not liable for exchange transactions, the health status of corals, or violations of species protection by users. A strict netiquette applies.

9.1 Public Visibility: By creating an entry, uploading images, or writing comments, you agree that this information is visible to all other registered users of the app.

9.2 Responsibility for Content: You are solely responsible for the correctness and legality of the data published by you. It is strictly prohibited to publish false information, third-party data without their consent, or illegal content.

9.3 Risk of Interaction: The community functions serve for networking. You acknowledge that other users can contact you, like or comment on your posts. All interactions take place at your own risk.

9.4 Disclaimer for User Behavior: The author assumes no liability for the behavior of other users (e.g., harassment, fraud). We urgently recommend taking safety precautions for private meetings or handovers.

9.5 Data Security: Absolute protection against screenshots or data theft by other users cannot be technically guaranteed. Only share data and images where you accept potential public disclosure.

9.6 Image Rights & Media Uploads: By uploading images (e.g., of aquariums or corals), you assure that you are the author or possess the unrestricted usage rights. You indemnify the app operator from any third-party claims regarding copyright infringements. Uploading offensive, violence-glorifying, or off-topic content is prohibited.

9.7 Netiquette & Moderation: A respectful tone applies to comments and messages. Insults, hate speech, spam, and bullying will not be tolerated. The operator reserves the right to delete content without warning and to permanently ban users in case of violations.

9.8 Swap Meet & Contractual Relationship: The app merely provides the technical platform. Contracts regarding the exchange or sale of corals/accessories are concluded exclusively between the users. The app operator is not a contracting party and is not liable for material defects, health status of animals, or payment defaults.

9.9 Species Protection (CITES): The user pledges to comply with all applicable species protection laws (e.g., CITES certificate requirement) when offering animals. Offering protected species without required proof of origin is strictly prohibited on this platform and leads to immediate banning and possibly reporting to authorities.

10. CHANGES TO THE TERMS OF USE

Summary: The author can change these terms. Continued use of the app requires your active consent to the new terms.

10.1 Right to Change and User Consent: The author reserves the right to change or supplement these Terms of Use at any time, especially if this becomes necessary due to changes in the law, changes in case law, or the introduction of new functions. The user will be informed about significant changes via a dialog when starting the app. Further use of the app is only possible after active and express consent to the changed Terms of Use by clicking a corresponding button ('I agree' or similar). If the user does not agree to the new terms, the app can no longer be used. In this case, the user has the right to terminate the contract according to the regulations in Section 7.

11. SEVERABILITY CLAUSE & APPLICABLE LAW

Summary: Ineffective clauses do not affect the rest. German law applies. Jurisdiction is the seat of the provider (or residence of the user).

11.1 These Terms of Use are subject to the law of the Federal Republic of Germany, excluding the UN Sales Law (CISG).

11.2 The place of jurisdiction for all disputes arising from or in connection with these Terms of Use is, as far as legally permissible, the seat of the provider. However, the provider is also entitled to sue the user at their court of residence.

Status: July 30, 2025