thanks both
finally got my dosing pump up and running
maintaining kh 9, ca 440, mg unknown
mix 6 spoon of NaHCO3 with 1l of water, dose 20ml every 3 hours
mix 6 spoon of CaCl with 1l of water, dose 20ml every 4 hours
mix 4 spoon of MgCl2 with 1l of water, dose 20ml every 4 hours
as my dosing pump can only select hour interval
i have no choice but to dose ca & mg together
at the "12" hour, all 3 will dose back to back
cheers