Ohio Rev. Code Ann. § 3121.45

Any payment of money by the person responsible for the support payments under a support order to the person entitled to receive the support payments that is not made to the office of child support, or to the child support enforcement agency administering the support order under sections 3125.27 to 3125.30 of the Revised Code, shall not be considered a payment of support under the support order and, unless the payment is made to discharge an obligation other than support, shall be deemed to be a gift.