Adding supplements

Prolly Mag, Calc, Alk, Strontium, Molybdenum, maybe. depends on how he is setting up his tank.

 

After water change concentration =( ( water volume left in tank * its concentration ) / (water volume of change water * its concentration) ) / total volume

 

so the water change water shouldn't be at the ideal parameters before adding to the tank?

 

The water change water should be above the levels you want the tank to end up at. Specifically, if you do a 25% water change, you want the WC water to be 3x greater than the difference between your DT levels and your targets.

So, for example, if your DT is at 420 calcium, and you wanted to get to 440 calcium on a 25% WC, you want the WC water to be at 440 + 20 * 3 = 500.

 

just a word on the speed of raising levels
you want to take 6 days, to increase a DKH level of 4 to a new level of 10
dont try to do this in 1 water change

magnesium - you want to take 2 days to increase it from 1225 to 1400
not try and fix that in 1 water change

Steve