I have! I bought 10 seedpods and planted 5 in an NPT, and the other 5 were taped to the glass above the substrate, bare rooted. The 5 in the substrate grew at least twice as quick, but they are still slow growers.
The only problem I had was that our NPT substrates are 1.5 - 2 inches deep, and as soon as the roots hit the bottom glass they grow along it, sideways! The roots are very hard/firm, so if you attempt to bend or shape them they will break. I only kept them an the NPT for a few months before moving them to my big tank, but the best growth happened in the NPT! If I were to try them again, I would still keep the 2 inch substrate, only I would pull up the mangroves every week or every other week to keep the roots growing down. taping the seedpods to dowels helped immensely in keeping them upright, and sliding them up a bit on the dowel slowly to raise the roots up helped in keeping the mess down. Once I had the desired root/tree height for the tank, I would quit uprooting them and let them establish their roots for good!
I don't think they are demanding at all, I grew them in 1.2 watts per gallon of T8 lighting and the leaves looked fine. Of course the growing stems were very leggy, so if you have 2WPG the trees should do real well. My water is extremely soft, almost no hardness, so if I could grow them you should be able, too!
Last thing, you will want to check the root growth periodically and make sure the roots don't press against the walls of the tank. It won't happen over night by any means, but these roots are very strong compared to my willows, and I have no doubt that the mangroves would happily grow right through the glass! Keep us updated if you get some!
