The 28% sodium chlorite solution should be stored at cooler temperatures and out of direct light.
The lower temperature limit is around 32 F. Don't store it at temperatures below 32 F.
The upper limit is around 200 F. Don't store it in an area where the temperature gets above 200 F.
UV light will break down the mixture and it will become ineffective. Sunlight and incandescent lights are a good source of UV light. Keep your solution away from these light sources.