1. Prime. Ordinarily we don't use this to condition water for the tank, but what you use in a Quarantine or Rescue or Hospital tank---no consequence to the tank. It's ok to create salt water even if you don't have ro/di on hand. It can also de-chlorinate your hands.
2. Carbon. Can sop up chemical snits among corals, or the fact your nephew put his toy truck in your tank. Cheerios are a separate threat. Net and massive water change.
3. PolyFilter: a resin pad that both identifies a mystery metal contaminant AND binds it to the pad, removing the threat. A mere snip off the expensive pad can be used to ID or confirm a problem before you go whole hog for the entire pad and use it up.
4. Salt. Being caught with no salt on New Years Eve is bad news. Keep enough on hand to replace ALL your water if you have to---but don't let it near moisture: A brick is what will result, with diminished usefulness.
2. Carbon. Can sop up chemical snits among corals, or the fact your nephew put his toy truck in your tank. Cheerios are a separate threat. Net and massive water change.
3. PolyFilter: a resin pad that both identifies a mystery metal contaminant AND binds it to the pad, removing the threat. A mere snip off the expensive pad can be used to ID or confirm a problem before you go whole hog for the entire pad and use it up.
4. Salt. Being caught with no salt on New Years Eve is bad news. Keep enough on hand to replace ALL your water if you have to---but don't let it near moisture: A brick is what will result, with diminished usefulness.