Ratio by PPM value (eg)
2ppm (Mg) x 3= 6ppm of (Ca) or 2 (Mg) x 4= 8ppm of (Ca)
5.75ppm (Mg) x 3= 17.25ppm of (Ca) or 5.75ppm x 4= 23ppm of (Ca)
Now the above ratio is not absolute so don't get caught up with it, it's only a guide. The plants don't care about the ratio really, what is important is that you have enough of each as to not cause a problem. For example I use a 1:8.33 ratio
