[Canadian Man]

Originally Posted by reef_raf

Chad, the Hagen has two options, carbonate and general. The general will let you add drops forever as it's measuring Mg as well as Ca.
That being said, I'd still throw it out and get a Salifert or other recommended good kit. The Hagen I used when I started gave me wrong measurements every time.

Brad that tester from hagen is the hardness test kit not the Calcium test kit.
Chad, 20 drops of # 3 would come out to be 400mg/l for calcium which is not extremely high. I have used hagen test kit's since day one and they work great, are cheep and easy to use. With the calcium kit you have to make sure you shake # 2 for about a minute.

1 Drop of # 3 is = to 20mg/l of calcium.

hope that helps