Your local code may require the grounding. I understand from questioning one of our local inspectors that this is a requirement for pools that have a 120 volt pool light but not when using a low voltage LED light. I have an excerpt from the Ontario Electrical Code.
*********************************************
Section 68 - Pools, Tubs, and spas
68-000 Scope
(2) A pool shall be deemed to include: (c) Spas and hot tubs
68-058 Bonding to Ground
(2) Pool reinforcing steel shall be bonded with a minimum of four connections equally spaced around the perimeter.
(7)Notwithstanding Subrule (1), the metal parts of a pool need not be bonded to ground or to each other where the electrical equipment associated with the pool is:(b) Suitably separated from the pool by a fence, wall, or other barrier.
*********************************************
The bottom line here is that I don't need to ground the mesh under my hot tub. Electrical code is all about interpretation. Ask your local inspector.