In the 1500-l tanks, TAN decreased from 112.9
(± 28.79) μmol l−1 to 35.1 (± 15.42) μmol l−1 in Gracilaria
tanks and to 65.1 (± 21.84) μmol l−1 in the tanks
with Chondrus. The outflow of the Gracilaria unit had
a TAN concentration of 18.6 (± 8.71) μmol l−1
, while
the outflow of Chondrus+Gracilaria unit had 21.6
(± 9.19) μmol l−1
. Total N removal by each cascade
unit (one 1500-l and one 300-l tank) was 2.45 g day−1
for cascade 2 and 2.36 g day−1 for cascade 3 (Table 3).
This represented an average of 14.43 g of N removed
per day by the complete system, or 1.20 g N day−1 m−2
of tanks.