No shower for 3 days due to necessary repair

[Katie Berry]

I am a new landlord and need to replace the only shower in our rental property, which will take 3 days to complete. The tenants will be staying at the premises for the duration of the repair and expect compensation for the inconvenience/impact. We offered them 25% rent reduction in daily rent throughout the course of the 3 day repair, but they have countered with expecting a full days rent reduced for each day. What are we legally required to prorate/deduct in rent considering it is their only shower and will not have one for 3 days? Thank you!