Till version 4.43, Waterspeed can consume a lot of space on your device. We have done an upgrade to fix it and the best way to apply it is:

• verify to have everything uploaded to the cloud, accessing www.waterspeedapp.com/webapp
• if something is missing, verify the login from the app and the Diary. In case it is showing some upload, wait till completed. In case, you can, manually re-upload a specific activity, inside the activity page, in the Share button
• when everything is uploaded, uninstall the app and reinstall it from the App Store
• Login again and download all data

Please note that this operation might remove all activities from the Apple Watch App and can't be restored.