2 Part Dosing

[Wretch]

Ok still need a little help. My calcium is at 450 my alk is at 8 and magnesium is at 1350.

After checking my alk every day it turns out I am using .3 dkh every day. So according to the 2 part calculator I need to add 12ml a day of alk solution.

My only question is about water changes. I have about 55g of water in my system and do 5g water changes once a week. My salt usually mixes up around 10dkh. So what is the best way to keep alk at 8?

Should I dose a little less then needed so when I do my water changes it brings it back to 8?