honestly on my 90 gal planted tank its just my old reef bulbs 2 10k 175w halides and 2 20k vhos and i get good growth, not great but the colors look good, for my mangroves/seagrass, i have 1 6700k de halide. 6700k is the best, and more isnt always better on planted tanks. For my mangrove system i wanted seagrass too, and i wanted to be able to raise the pendent up and the grass has strong light needs, so i didnt want to raise it up with a lower power light and starve the sea grass of light so i went higher light, a 70 w would have worked with no seagrass and just regular macro. some t5s would work fine or a couple pcs would work well and be cheap to do. the mangroves took awhile to get started, i first started them touching substrate (sand in a plastic container in the system, once the roots became stimulated i tied them with green plastic plant tie that you find at home depot. The next thing is stability, they neet the same thing every day, in the wild once they end upn where they are going to grow its a mad dash to get roots in the sand so they dont get washed away. from what i understand the stability of the same light/water conditons all the time make the plant think the plant has settled and it takes off. i mist mine when im home a couple times a day. this is probably overkill but i figure the faster the salt gets off the plant the more it can transpire. also some people like to put them so just the tips of the top of the plant is out of the water, i took another track and put just the bottom inch under water, the plant has to transpire and get water to the leaf while dealing with salts, i figured the less salt it is imersed in the better. this is mostly conjecture and my experience. i didnt know anything about them when i started, but it turned out ok.