So far in my brackish, my prettiest and favorite of all time is the tiger lotus. If you have brackish you should look in to getting this plant. I bought mine at aquariumplants.com. Mine arrived as little bulbs and once they started sprouting in a few weeks, they did not stop! So pretty!!
Also Dwarf Sagittaria has made nice ground cover and is constantly sprouting runners.
I've also had great luck with Cryptocoryne wendtii and have had the same plant for many, many years. It survived a move from a 10 gal, to a 20 gal and is now making babies in my 75gal. This plant was originally fresh and is now brackish and has survived 2 pH crashes. Really hardy!!
I have 2 wpg and never dosed carbon until recently in the 75g I've been using Excel carbon.

