First, the vitals:
75 gallon tank, drilled with a 20 gallon sump (had cheato in the sump)
Approx. 80-90 lbs live rock and about a 3 inch sandbed.
RO/DI water currently reading 1 TDS
Ammonia, Nitrite, and Nitrate all read at zero.
All other parameters meet the specs for natural seawater (dkh, pH...