He does seem intent though. We cannot make them listen. Can you imagine what this concrete basement soak tub is going to look and smell like when everybody suds up and spills their beverages, scewered shrimp and all into the water. No systems for recycling the water through filters or at least copper plates?
Call me a negative person as some on the other thread did. I will say what I did there again though. You cannot plunk anything you plan to splash around in, an especially in your basement without thinking through---just to start---ways to get water in and out of it legally.
Call a pool or spa design team in for this. I find this self-poured concrete tub without reinforced walls to be one of the most dumb suggestions ever floated on this site. The OP will stick with us until he gets affirmation I am guessing.