Joining a bit late to add a couple of bits of info that may have not been provided before.
I've been to the Tuamotos 5 times. When diving in Fakarava North, I've always gone with Fakarava Diving Centre, now Kaina Plongee. If your email bounced, you can also try vincent perceval <vincentperceval@hotmail.com>.
When diving Fakarava South, I've always stayed in Tetamanu. Yes, no hot water, but it is doable. The night dive, it is a thrill......in my opinion, it beats the night dive in Cocos with the white tip reef sharks in the number of frenzies, so to me, it is definitely worth doing even tho it is more expensive than the day dives and are only 35 minutes. BUT, it is my belief that the action is in direct proportion with the amount of light being shined onto the reef, so more divers and high lumen lights (>2000 lumens wide beam) help.