2.2. Water chemistry
The physico-chemical condition of water including
water temperature, pH, dissolved oxygen (DO), total
dissolved solids (TDS), conductivity were measured
early in the morning prior to feeding at a depth of
20 cm by using a multiparameter water analysis
instrument (model No.Multi 340i, WTW, Germany).
Total alkalinity and total hardness were determined by
the sulphuric acid titration method as per APHA
(1989). Parameters like nitrate (NO3) and phosphate
(PO4) were determined on weekly basis by using
spectrophotometer (Spectroquant NOVA 60,). Ammonia
and nitrite concentrations were determined at the
same time using spectrophotometer kits. Dead larvae
were removed and counted twice a day, simultaneously
to water changes, to estimate the percentage of
survival rate per 24 h. On the last day of the
experiment, all the remaining larvae were individually
counted for the calculation of actual survival rate.
2.2. Water chemistry
The physico-chemical condition of water including
water temperature, pH, dissolved oxygen (DO), total
dissolved solids (TDS), conductivity were measured
early in the morning prior to feeding at a depth of
20 cm by using a multiparameter water analysis
instrument (model No.Multi 340i, WTW, Germany).
Total alkalinity and total hardness were determined by
the sulphuric acid titration method as per APHA
(1989). Parameters like nitrate (NO3) and phosphate
(PO4) were determined on weekly basis by using
spectrophotometer (Spectroquant NOVA 60,). Ammonia
and nitrite concentrations were determined at the
same time using spectrophotometer kits. Dead larvae
were removed and counted twice a day, simultaneously
to water changes, to estimate the percentage of
survival rate per 24 h. On the last day of the
experiment, all the remaining larvae were individually
counted for the calculation of actual survival rate.
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