Top up and water change?

[Davoaldo]

I use to use tap water to top up and do water change. I know it contain all the nasties but it also contain some goodies like "calcium".

I have recently purchased a RO/DI, if I change wateror top-up with that won't I have to dump in a whole heap of calcium additive and other supplements?

[Dustyy]

get a good salt mix and it will help on the calcium

[HornetMech242]

Well you start with testing the top off water and the mixed water change water and then you can add anything before it goes into the tank. the trick is to get it as close to the tank water so that parameters stay the same to avoid any stress or shock to the animals. Dont fully rely on the salt mix to have thel evel of calcium that you want.

Edit: Test for anything that you add so that you dont over dose.

Chris