Can I use DIN and PO4 in the given formula :

The trophic index (TRIX) used in the present work has been given by the following formulation (Vollenweideret al.1998):

TRIX = [log(Chla∙ (D%)O2 ∙ TN ∙ TP)] − (−1.5)⁄1.2

Where:

• Chl-a - Chlorophyll-a concentration (mg/m3 )

• (D%)O2 – The % deviation of the oxygen concentration from saturation conditions (abs [100-%O])

• TN - Total nitrogen (µg/l)

• TP - Total phosphorus (µg/l)