Day #2. Water Change Regime Continues

Removing Nitrate is done gradually, avoiding the acute effect from extreme water change. Extreme Water Change could expose higher risk to stress, WC sparingly.  
Filter media backwashed with removed tank water. 
30% volume from the tank was displaced with an Aged (chlorine treated & aerated) water. 
System was left to settle before Nitrate test was performed. 
The test result is as below. 

There is a reasonable improvement from the night before.