Hastings Spa, Private Sauna's swimsuit requirement?

We're looking for some good spa places, and a noticed that a lot of Redditors recommended this one. I have some awkward questions, but I'm genuinely curious.

If we book a private sauna room, do we need to bring swimsuits or t-shirts, or is it okay to go in naked?

We're debating whether we need to buy clothes for the spa, as we’re visiting Vancouver from the island with just backpacks... What’s the setup like when you book a room?

I figured that this is an weird question but we had purchased too many swimsuits already for the same reasons lol.

Thanks!