Ok, thanks. So you are getting a significant amount of your Alk and Ca in balanced ratios from the Kalk before you adjust with adding carbonate or calcium directly. I don’t know how much exactly but probably significantly more than half given the numbers you said. I think Randy’s DIY is set up to dose equal amounts if I remember correctly.So over the years. This is what works for me. I estimate I have approximately 250 gallons. Since I live in San Francisco evaporation is constant. I’m guessing evaporation is about 2 gallons a day. I use a litremeter thru a Kalk stir. Then I dos Randy’s diy recipe. To make up the rest. Banking soda baked for a hour. Brs calcium. Magnesium is Randy’s diy. I keep alk around 9 cal 450 mag 1500. I check everything once a week with Hanna checkers. As of now I dos alk 52ml and cal 12ml. So I guess that’s more like 80/20ish. Mag I just check and dump it in as mag doesn’t move fast.
But it’s always been like this.
This matters because say for example the kalk is supplying 80% of your Alk and Ca in balanced amounts. Then the differential you describe of 80% dosing balanced and 20% dosed 4:1 is really not that far off from dosing within 10% of balanced.