N.Y. Comp. Codes R. & Regs. tit. 10, § 6-1.25 – Spa pools; additional requirements.

(a) Spa pools shall be operated to meet the specific requirements listed in this section, in addition to other applicable sections of this Subpart.
(b) The maximum water temperature for spa pools shall not exceed 104° F. A thermostatic control for the water shall be provided. An audible alarm system shall be installed and maintained to warn of any temperature over 104°F.
1. (1) The pH of water in the spa pool shall be maintained between 7.2 and 7.8, and a minimum free residual chlorine of 1.5 mg/l shall be provided. Spa pools shall be chlorinated to 10 mg/l at least once a week when the pool is not in use. A maximum of 5.0 mg/l of free chlorine residual shall be permitted during use.
2. (2) Where bromine is used as the disinfectant, a minimum bromine residual shall be maintained between 3 mg/l and 6 mg/l, and the pH shall be maintained between 7.2 and 7.8.
(c)
(d) Spa pools shall be drained and cleaned when needed, and at least once every two weeks.
(e) A warning sign with an area of at least three square feet, stating the six caution statements contained in section 6-1.29, item 14.13, of this Subpart, shall be conspicuously posted in the immediate vicinity of the spa pool.