Honestly I dont know am just been dummy I gues..I tought since water has already passed thru carbon and sediment filter before be dumped,it may be cleaner than tap water..sorry am just trying to understand fresh water..may even use my clean water I use for salt
no RODI water wont work for fresh water tanks either .. it doesnt have the needed ions.. and kill the fish ..
the salt we mix has them .
it purely depends on what you wanna keep in the fresh water tank ..
plants really dont care.
shrimp - regulars dont care , delicate species do ..
fish -- depends on the location where the fish is from, German blue rams and neon tetras ( most pretty ones haha ) prefer a ph value of close to 8 which is easily attainable by rodi water mixed with ions ( additives )
for basic fish just use the tap water with dechlorinator and you will be fine.