Yes, black tank, you are right. But unfortunately, due to work and family commitments, and lack of huge containers for large volume of new salt water, I have to do smaller volume change with higher frequency.
I did an approximate calculation, by the end of this month, I would have changed approximately 75% of the tank water. That is after a total of 14 water changes over a 2-month period. Challenge is whether I can persevere till end of this month! [emoji28]