here what i did when i had the 29BC
https://forums.saltwaterfish.com/t/338296/refugiums-for-all-nanos
and the mangrove:
The Red Mangrove can be planted in the sand, or in between rocks in an open topped aquarium, illuminated sump or refugium. The roots will quickly take hold in either a sand substrate or in live rock. Provide illumination for these plants through the light from the side of a metal halide, or directly under fluorescents with a light spectrum in the range of 6000°-8000°K.
Mangroves absorb nutrients from the water in order to grow, and help lower nitrates and phosphates in the aquarium. They export the unneeded nutrients and excess salt through their leaves. It is important for nutrient control in the aquarium, that when leaves are dropped from the plant that they are not allowed to decay in the aquarium.
This species of mangrove will grow in fresh, brackish and saltwater. They are even suitable for ponds in the Southern States where they will not be exposed to near freezing temperatures. Be sure when planting that the leaves are out of the water. They can also be simply planted in a pot and used as a house plant. Just be sure to keep its soil moist and to provide it with plenty of fertilizer.
The general care for these plants includes; wiping excess salt from the leaves with fresh water a few times per week, and trimming the growth tip of the plant to control growth. These plants will benefit from the regular addition of an iron supplement, and trace elements.