[John B.]

I just got back from the lfs where I bought a calcium test kit. After opening it I realized that it is for saltwater use. Can I use this kit to test my calcium, or did I just waste $15? If it matters it's an AP test kit.Thanks,
John

 

[trenac]

If it specifies for saltwater it can not be used on freshwater, if I'm not mistaken. Some test kits can be used on both saltwater/freshwater but it will say so on the label.

 

[shalu]

I have the AP kit and I can positively say that the readings are incorrect for freshwater. How do I know? Well, I added NaCl to simulate saltwater to some degree, and the Ca result is VERY different from the result without salt addition.

For a cheap one that works for freshwater, Hagen kit is recommended on this forum.