Typically a reasonable salary is what someone else would get paid to do what you are doing. Since you are an owner of a real estate venture, your income would likely consist of rental income, which is not treated as wage income. It would be reported on line 2 on your S Corporation Schedule K-1 as Net rental real estate income (loss) and be reported on Schedule E on your personal tax return.
hopefully, you have net rental income. otherwise, you may unknowingly have basis problems that would bar you from taking the losses. in an S-Corp mortgages do not count towards tax basis like it would if you held the property personally or through a partnership/llc taxed as such.
example: you put in $20K cash, take out an $80K mortgage and elect S-Corp for your SMLLC. the maximum amount of losses you can deduct is $20K (the mortgage doesn't add to your tax basis) unless you put in more money personally. take cash out and that reduces the losses allowed(able) and can even result in taxable income.
in a partnership/LLC you could take up to $100K in losses. the mortgage counts toward s tax basis.