You salt has iodine in it and at the levels it should be.So there is no need to dose iodine.Especially if your not testing it.
On the PH.Test it about 15 minutes before the lights are out for the night.That's when it'll be its highest.If it's still reading 8.1 , then we'll try to figure out what's causing it to run a tad low.
Also check your alkalinity.
To add: as long as you do weekly or even bi-weekly water changes you dont need to worry about elements. The only thing I use is MicroVert which is coral food and Essential elements, but both with a low dosing. I use 0.1 ml per gallon of Essentials.
On the PH.Test it about 15 minutes before the lights are out for the night.That's when it'll be its highest.If it's still reading 8.1 , then we'll try to figure out what's causing it to run a tad low.
Also check your alkalinity.
The PH will drop at night because the algae stops producing oxygen when there is no light.The increased oxygen during the day will raise the PH.At night,an increase on CO2 will drop the PH.
+1 everyone. No need to mess with your pH or dose iodine. The corals look nice and healthy. Hannah is right -- they will look slightly different under different lights.