No 100% water change at any time! You need to change water 20-25% a week! full water change break the nitrogen cycle which u can aware by googling niteogen cycle! Never do full water change!! And mineral water in my opinion is to clear for the aquarium which sometime a stressfull to fish. U try to change mineral to tap water in few next water changes so that would have balance for 20% mineral ( means the RO water) and 80% tap water. but be careful do not do it over the night, do it gradually so u will not fluctuate the water pH.
100% water change kills the fish as it breaks the good becteria bed.
Also, the filter spongue and other media should be clean with aquarium water only, never clean media with tap water, I do the same and my aquarium balance is good..
Also, to make the tap water safe, u can use the water conditioner like seachem or any other which is good! Use the instruction how to use water conditioners.
100% water change kills the fish as it breaks the good becteria bed.
Also, the filter spongue and other media should be clean with aquarium water only, never clean media with tap water, I do the same and my aquarium balance is good..
Also, to make the tap water safe, u can use the water conditioner like seachem or any other which is good! Use the instruction how to use water conditioners.