Please help with this!!!!!!!!!!!!!!!!!!!!!!!!!!!

Please refer to the following pics. We have been dealing with this for 4 months. We have tried cleaning this up daily but to no avail. We decide to let it grow to to a size we could take a pic. This is about 2 weeks of growth. Right know we have a crushed coral bottom but are moving in June so we will be changing to a sand bottom. It seems to be growing more rapidly near or on our non-live rocks. We have about 4 pieces left in our tank from about 6 years ago.
Tank specs for April 16, 2005
PO4 0 - .25
Ca 380 which we know is low
NO3 less than 5
Ph 7.9
Kh 90
Fe 0
NO2 Less than .1
NH3 0