Hello, thank you for your review, I am sorry that the product did not meet your expectations. With air purifiers, the effect may not always be visible to the eye - especially in environments with less dust. The filter also captures particles that are not visible to the naked eye (e.g. pollen, odours, aerosols). However, if the product is really not working properly and is significantly loud, this may also be a fault. We recommend contacting our support with details - we'll be happy to check everything. As for the bugs in the app, we would be happy to receive your suggestions so that we can check them and ideally fix them. Please get in touch with suggestions at
[email protected]. Thank you and have a nice day, Ondřej - Alza expert