Should I have to add anything to my RO/DI water to make it safe. I ask because my tap water has ammonia in it. I just bought a new RO/DI. I used to put ammo lock it before. Is there any need for this now with a RO/DI??
Agreed- if adding commercial salt mix to R/O water, that will add the necessary buffers and minerals. If you are using R/O to top up with freshwater, add a PH buffer to bring the PH to the proper range (Kent and Seachem both have good products, there are others too). I always add water conditioner to my R/O water as an added precaution to neutralize any remaining metals (though there shouldn't be any).
I sort of disagree with part of that statement. RO water has very little buffering and your tank should have a lot of buffering capacity. A small amount of unbuffered RO water added to a big amount of very buffered saltwater equals a big amount of very buffered saltwater. It doesn't matter what the pH of your RO water is, the tank will still be at the same pH as before you added the makeup water.
I was always told you had to add buffer to your top off water. I have been adding AragaMilk to my all my RO/DI water. Any one else have a opinion on this?
Aragamilk is just a way to supplement both Ca++ and Alk. You could also drip kalk or use a 2 part additive or buy a calcium reactor. All different ways of doing the same thing--maintaining Ca++ and alkalinity. You don't need to add anything to the makeup water.