Thunderdome

I live in a house that has a hot tub in the garden. The landlord says it doesn't work but I have no idea how to know exactly what is wrong with it. Below are pictures of the tub. I'm not sure how to troubleshoot the issues it may have, what the name and model are, and who to reach out to for help. At the very least it needs a cleaning. I'm in the San Francisco Bay Area.