i did a search on it and this is what i found hope it helps
* Read thoroughly before testing. Do not allow test solutions to get into aquarium.
* To remove childproof safety cap: With one hand, push red tab left with thumb while unscrewing cap with free hand.
o Rinse a clean test tube with the water being tested.
o Fill the test tube to the line with the water being tested.
o Holding the bottle vertically, add 10 drops of Calcium Test Solution #1 to the test tube, cap and shake for 10 seconds.
o Shake Calcium Test Solution #2 bottle vigorously for 10 seconds.
o Holding the bottle vertically, add Calcium Test Solution #2, drop by drop to the test tube until the solution changes from pink to the blue end-point. Each drop is equivalent to 20 mg/L (ppm) calcium (Ca2+). Cap and shake the test tube between drops. Be sure to count the drops added.
+ A pink color should form after the first drop.
+ If a blue color forms after the first drop, the calcium concentration is 20 mg/L (ppm) or below.
o As the end-point is approached, the color will usually change from pink to purple before finally changing to blue. After the purple color forms, only one or two more drops should be required to reach the blue endpoint.
Note: Reef aquariums should have a calcium (Ca2+) concentration of between 400 to 500 mg/L (ppm). To save time, rather than adding only one drop at at time, several drops of Calcium Test Solution #2 may be added simultaneously at first, then the final drops can be added drop by drop as the endpoint is approached.
For example, if you think that the saltwater being tested contains about 400 mg/L (ppm) calcium, you can add 10 to 15 drops of Calcium Test Solution #2 at once as indicated in step 5, then cap and shake. If the solution is pink, continue adding drops, one at a time, until the end point is reached. If the solution is blue, then too many drops were added and the test must be repeated, adding fewer drops initially or adding the drops one at a time.
