I have used this salt for a number of years with no issues. Recently I noticed that it now has an additive included, by searching the MSDS thes are described as the ingredients:
Sodium Chloride 99.97%
Sodium Hexametaphosphate 0.03%
The question is in a 10,000 gallon pool how much phosphate in ppm would a 40 lb bag introduce? As it is less than half the cost of pool salt from the local pool store I would like to keep using it but not if it raises the phosphate level too high. This would be especially a concern in a drain and fill situation.
Any help would be appreciated.