Sodium citrate is what most commercial gels use instead of table salt. Same sodium content but no chloride bite, so it tastes cleaner and slightly tart rather than salty. At high intake rates (80–90g carbs/hr over 5+ hours) the "salty gel" flavor can become unpleasant — sodium citrate sidesteps that. Maurten uses it. GU uses it. It's also slightly easier on the stomach for some people.

Potassium chloride (salt substitute) covers a secondary electrolyte loss. You sweat potassium too, just less than sodium — roughly 150–200mg/hr vs your 1,100mg/hr sodium. It's not a priority fix but rounds out the electrolyte profile on very long efforts. Tastes slightly bitter/metallic in large amounts, so a little goes a long way.

Practical swap for a 500ml batch (scaled on this page for flask size and number of flasks): instead of 1 tsp table salt, use ¾ tsp sodium citrate (~510mg sodium from ¾ tsp × 680mg/tsp, cleaner taste) and ⅛ tsp potassium chloride (~53mg potassium at base 1/16 tsp × 840mg K/tsp).

Live batch sodium from your slider: 340mg per flask batch (1/2 tsp × 680mg Na/tsp).