What did you make your saltwater with? Faucet water? Or did you have RODI water?
The PhosGuard is probably to pull the phosphates / silicates out of the water if you do not use RODI.
Brightwell Aquatics MicroBacter7 some people may recommend soaking whichever biomedia you are going to use in a bucket of saltwater with an airstone and add the bacteria there for a few days. This will help with your cycle.
Carbon, I only ever use to remove meds from my water, so I can't speak for that.
I do have RO/DI system here at my school and used that