Personally, I wouldn't use "tufa" or "tuffa" rock (two different rocks). Find dried live rock instead.
www.bulkreefsupply.com has good prices on theirs including shipping. There are a few other companies out there too (like Marco Rocks), but they will kill you on shipping. You can have as little as just one piece of live rock in a tank of dead rock, and it will eventually seed all of the dead rock, but the more live rock, and less dead rock the quicker it will be seeded.
B
angaii Cardinals can be tough fish to keep. Once they reach maturity they will pair off, and any outsiders will be severely picked on. On the other hand, once you have a pair they will start to breed. The male holds the eggs in his mouth for 5 weeks, and doesn't eat for that entire time. Once the male expels the fry after 5 weeks the female will be ready to pump him full of eggs within a week afterward. If it carries on like this the male will starve to death. The best bet is to get a "dud" pair where the male will either expel the eggs prematurely or eat them, and they will live happily ever after. For these reasons, I am really starting to believe that Bangaiis are better suited in small shoals in 100+g tanks where they can hide from eachother.
Imo, a sandbed of 1-2" is optimal. Deeper sandbeds tend to get sulpherous gas buildup, and release toxins over the years. Deep sandbeds are a bit of a thing of the past these days. Those detrivore kits look kinda interesting, however I think they may be a bit of a waste of money if you're buying live rock as you will get most of those critters with the live rock you buy at no extra charge.
