Just mixed up some IO, Ca not so good

[fencer]

Are you using magnesium chloride or sulfate(epsom salt)? And how fast does the mg drop in your tank?

[Captainhemo]

According to Littlesilvermax, Food grade magnesium chloride mixed with a small amount of magnesium sulfate (I used Randys Recipe in the Calculator to get my mg in the ballpark).

By dosing my weekly water change water to desired levels my Mg has stayed at 1300 (Elos ) since I got it up to that. I have to add about 1.5 Tsp / week of Ca to keep Ca at 400 (I used Dow's Flake in the Calculator).