Rainer
Contributor
Richard, are you sure you aren't confusing the NAUI term helitrox (note the "tr") and heliox. Everyone I know who uses the latter is referring to a mix of only helium and oxygen (i.e. what most commercial and military divers use on deep dives).
Well I thought the US Navy considered heliox any mix of helium and O2 and the term is used that way in commercial diving. But recreationally NAUI and others here in the States consider heliox any trimix with >normoxic levels of O2. Things like 26/17, 25/25, and 30/30 are all considered "heliox" here (althought the term is not common).
Trimix being the more generic term for any combo of O2/He/N2