Mangroves work really well, but grow fast. I had mine in refugium that was plumbed into the main tank. Leave a leaf or two, but clip ALL the rest. Also, this thing is a tree...it will get large, so expect to replace them when they get too big with the seedlings again. You can prune it a few times, but it gets thicker as it ages. Some great deals can be had on Ebay (I think the last time I got 10 stalks for $10, plus $8 shipping). There are more efficient nutrient exports that are less maintenance (though small trees sprouting form your fuge definitely is a conversation starter)...Oh and if you happen to have a seahorse tank, they seem to really like hanging on to them...
yeah my fuge became a seahorse tank after I found a pair of starving seahorses at Pet Club....