I have a SW tank and a FW tank so I have a 40 gal garbage can of each heated to 79F with a bubble stone running. After a water change I refill the SW can with the FW and mix the salt with a submersible pump. Then refill the FW can with RO/DI water. Works for me

Victoria source water is very good but I would still use RO/DI. The water comes from a protected lake at the top of the mountain to a treatment center that treats with UV (ultraviolet light) and then adds chlorine. This method provides double barrier protection making the water very safe to drink. The problem is that there are still compounds (metals, silicates, dirt, etc) that may be present in the water that are not removed. These items are only removed by the use of RO/DI treatment.

BTW I did the programming for all the UV systems which is how I know all about their water system.

There is no water supply system in the world that will bring water to your house at the quality of an RO/DI membrane will produce. Even the new water reclamation projects that treat the water through RO filters will not be at RO quality by the time it reaches your house. The pipes will have some debris, draw in groundwater, leach copper, etc all of which are safe for drinking but could build up/cause problems in the fish tank.