corals basic needs:
stability in water
99% need light
water flow
Alk, Calcium, Mag
exportation of nutrients, i.e., nitrates & phosphates
however, a small tank with a light bioload and soft corals and a few lps can usually meet all those needs with large weekly water changes (as long as PH & salinity match).
So soft corals, i.e., mushrooms, etc.... really don't need much, IMHO.
let me regurgitate

some links, so you can get some basic needs met.
brought to you by Randy! lol
http://www.reefkeeping.com/issues/2004-05/rhf/index.htm"><span style="color: #22229c">http://www.reefkeeping.com/issues/2004-05/rhf/index.htm</span></a>
[IMG]http://web.archive.org/web/20021127040526/http://www.advancedaquarist.com/issues/nov2002/chem.htm"><span style="color: #22229c">http://web.archive.org/web/200211270...v2002/chem.htm</span></a>
[IMG]http://reefkeeping.com/issues/2006-06/rhf/index.php"><span style="color: #22229c">http://reefkeeping.com/issues/2006-06/rhf/index.php</span></a>
[IMG]http://www.advancedaquarist.com/2002/11/chemistry"><span style="color: #22229c">http://www.advancedaquarist.com/2002/11/chemistry</span></a>
[IMG]http://www.advancedaquarist.com/2003/2/chemistry"><span style="color: #22229c">http://www.advancedaquarist.com/2003/2/chemistry</span></a>
I would concentrate on getting a 2 part, like this:
[IMG]http://www.bulkreefsupply.com/brs-2-part-calcium-alkalinity-total-package-bulk.html"><span style="color: #22229c">http://www.bulkreefsupply.com/brs-2-...kage-bulk.html</span></a>
and mag like this:
[IMG]http://www.bulkreefsupply.com/2-part-magnesium-mix-aquarium-supplement.html"><span style="color: #22229c">http://www.bulkreefsupply.com/2-part...upplement.html</span></a>
all this can be bought locally, too!
just add ALK, Calcium, & mag using a calculator:
[IMG]http://www.bulkreefsupply.com/reef-calculator"><span style="color: #22229c">http://www.bulkreefsupply.com/reef-calculator</span></a>
(get some test kits for all 3 from Elos or Salifert)
here are some:
[IMG]http://www.liveaquaria.com/product/aquarium-fish-supplies.cfm?c=597+2856">http://www.liveaquaria.com/product/aquarium-fish-supplies.cfm?c=597+2856</a>