Neutr-All is a liquid ‘sanitizer eliminator’. Called Sodium Thiosulphate in the industry, this product completely disables any active Chlorine or Bromine in the hot tub water. It is so powerful in fact that it will instantly reduce or completely neutralize all the sanitizer – making it very important to follow the correct dosage on the label. Overdosing with Neutr-All can affect the free available chlorine reading on your next fresh fill. Neutr-All makes the hot tub water safe to drain.