Do I add anything back into my RO DI water prior to use?

[rkb]

Other than salt mix of course... But seriously, Seachem and others offer mixes to put back some minerals etc. back into the water after purification. I presume these additives are to raise/stabilize GH or KH and the like. Is this something that I need to look into OR does my salt mix do the same thing?

As always, thanks for the help RC

Russell

[Randy Holmes-Farley]

No, adding anything else is undesirable, unless you determine that the salt mix, once prepared, is lacking in something (such as it having low calcium).

No salt mixes are deficient in alkalinity that I've seen.

[nwpschris]

What about for top off water? Is there anything that is beneficial to add to DI top off water before it goes into the sump? Maybe a little kalk?

[Randy Holmes-Farley]

Evaporation is pure water, so replacing it with pure water is appropriate. :)

You can certainly use to off water to deliver many things the tank needs, but the emphasis is on the needs of the tank, not the "needs" of the RO/Di water. I use limewater top off to maintain calcium and alkalinity, for example.