I ordered some hardy red mangroves online, which cost me an arm and a leg since they are not native to Japan. (I had also tried growing native black mangroves, but they wilted in no time.)
Mine came sprouted from a plant specialty site, since I had missed all the aquarium store sales. I didn't know the salinity. For all I knew, these had been sprouted in tap water. It worried me, but I prayed for the best and decided to use them anyway.
I rinsed them off in a cup of tank water and stuck them in the fuge which has a plant light over it. Bad move.
The plant light was too close to the mangroves and burned leaves. One was burnt past usefulness (it turned rock hard) and so I stuck the two remaing in my main tank on top of the back of one of my live rock structures, close enough to receive some indirect light from my 150W MH.
This did the trick. The roots grew pretty vigorously to attach themselves to the tank. I get at least one set of big leaves every month and the burnt leaves have finally fallen off. And I never have to clean the leaves of salt like I have seen in some sites.