hey broomer, id be willing to send you a smaple of my water(up in beautiful colorado here) if you wanna test the sg at the altitude that you are at, or anyone else for that matter. this does really interest me because i am so high up 4,658 feet to be exact, so were not as high as denver, but still up there. i think im also going to have to splurge for a dissolved oxygen kit, cause i think it would be worthewhile to find out. this makes total sense, adn hen fish purchases here should wait for awhile after first being receive so that they can adjust to altitude as well as tank temp, salinity, etc. never really thoguht of this, just like someone coming to co, from ca or the coast! verrry interesting!
good luck
jon