We'd like to see all parameters:
Ca 420ppm
Alk ? Nit sure haven't test for it.
Ammonia 0 ppm
Nitrate 0ppm
N03 .5ppm
Salinity 1.025
Temp 77.1 to 78.6
pH 8.2
P04 0ppm
I just stated to dose iodine. Maybe that would help
If you don't have a kit for Alkalinity - you definitely do want to get one
As far as the iodine, before you dose for something, it's highly suggested that you test to see if you need it.
Iodine is in your salt mix, so you may not need it. Best to get an iodine test kit before you OD the tank on it and have a different/worse issue.
You listed:
Those are both the same thing (Nitrate).
What is the Nitrite result?