well here is the run down:
20 gal reef with 130 w p/c , hob skimmer,hob filter, 2 powerheads for flow
all water parameters good.
s/g 1.024, ph 8.2 , amonia 0, nitrite 0, nitrate not detectable,phos.>0.2
cal 480-520.........adding iodine,strontium,and trace once a week,
10-15% water change...