WOW. 6g daily? I've even got a medium sized dehumidifier in the basement whenr the tank is. I think I remember when I got back from my 7 day trip, I probably added about 7g total to my 72g w/sump. Now, I would not recommend that to a less established tank 'cause of the salt level swings (among other things), but I've been able to get along fine that way. Did it twice in the last couple of years. I also feeda little heavier for about 3 or 4 days prior to leaving.
Guess I've been lucky.
"Life may not be the party we hoped for but while we are here we might as well dance!"