Hi,
I think Arm & Hammer only sells their Super Washing Soda so I think you are smelling something else....your nose burning from the caustic powder ?
Washing soda is caustic and it will feel very slippery when dissolved in water. This can be confirmed by measuring the pH and it should be around 11.5. So, it is not a very good idea to smell this stuff. Washing soda is Sodium Carbonate and Baking Soda is Sodium Bicarbonate. You can also make washing soda by baking Baking Soda in the oven. Just bake at 350F for an hour or so. Again, you can use the pH method to figure out if you have washing or baking soda. Baking soda has a pH of around 7.8.
However, the main purpose of the 1 to 6 ratio is that the buffer solution has roughly the same pH as the NSW. Baking soda has a lower pH and Washing soda has a higher pH -- the correct ratio gives about 8.2-8.4 pH. There is nothing wrong with just adding baking soda or just washing soda, but the pH will temporarily shift a bit. However, this state is temporary and it will re-establish a new bicarbonate/carbonate ratio for the given tank conditions. The final ratio may be 1 to 7 or 1 to 6.5, but the water will automatically do that for us.
Hope that helps.
- Victor.