mangrove substrat

So I have my little mangrove, and have had it for about a month, not the leafs start to brown, and don’t know what I’m doing wrong, a had a couple rots braking of in transit but I did as recommended and glued them with Reef safe super glue, what can I do to save my tree? Should I pot it instead...

First off I want to say to R2R I think we should make a specific category for Refugiums/Macro Tanks. Super excited to be upgrading today! Going from a small (13") hang on back CPR Aqua Fuge to a medium (19") CPR Aqua Fuge 2. Brightwell Aquatics was kind enough to send me some Mangrove Substrat...