GroTech Magnesium Pro Liquid, 5000ml

With Magnesium pro liquid only the actually used magnesium should be replaced.

i.e.
First the actual magnesium value in the aquarium must be checked by a testing kit.

Now you have1200mg/litres magnesium in the aquarium and you would like to increase on 1300 mg/l.
They have a 500 litre basins.Mg content of Magnesium pro liquid 50.000 mg/litre

Desired mg value - actual value = deficit in mg/litre
1300mg/l - 1200mg/l = 100 mg/litres

Deficit in mg / litre x basin contents in litres = deficit in mg
100 mg/litres x 500 litre = 50.000 mg

Deficit in mg : Mgpro liquid 50,000 mg/litres = necessary addition in litres
50.000 mg : 50.000 mg/l = 1 litre

The shortfall should be admitted over the day distributed!
After few days you know the consumption of your aquarium of magnesium and you can add the daily consumption over a dosing pump.