71 to 78 is their proffered range in the wild. Depending on how your light setup is done, it shouldn't be hard to get in that range since your water is going to be close to that as well.
Just like most reef fish, Mangrove are tropical trees. They don't handle the cold well, the main limit on their natural habitat is low temperatures to far from the equator...And human chainsaws.
I really have to check the collection laws or local suppliers on these things too. I can live with leaving the ones that are needed in the environment alone. It's just gonna irk me if I have to have seedlings shipped in from somewhere across the country, for a tree that's growing 100 yards from my house. I might have to see if there's a construction site about to take some out and see if there's any seeds to be salvaged. The park rangers will prosecute in a heart beat if you try to collect something from the wild, but if you're building a new high rise, they'll hand you a chainsaw.