I agree with Abbeysdad.
On another note, please take some of those fish back. The cichlids will soon (never know which day, but it will be sudden) turn on everything in the tank and rip the mollies apart.
The puffer will soon turn on everything too, but it will probably die from water problems sooner rather than later. It needs brackish water. Google it.
Please research the fish you have, instead of listening to what the pet shop says. All they want is to make a sale.
Adding an airstone might help a little.
When your tank is cycled, stop adding the salt. Salt has no use in a freshwater tank. (salt levels for the puffer would be okay for the mollies, but not for the cichlids or CAE)
Please go out and buy a good water test kit. Tetra and API both make them. They will let you test the water for ammonia, nitrite, and nitrate
Welcome to the hobby.