ELOS Expert Line Aqua Test - Mg

ELOS brand test kits have a good reputation and appear to be comparable to Salifert test kits.
I found the kit reasonably easy to use but most magnesium kits are a bit tricky. This test kit is accurate to 50 mg/lt (ppm) as each drop of Reagent D is equal to 50 mg/lt (ppm).
Instructions:
Shake each bottle before use.
Fill testing vial to 3ml using syringe.
Add Reagent A drop by drop, counting each drop while swirling the vial until the color changes from orange-red to green. The color change should be stable for at least 30 seconds. Make note of the number of drops.
Rinse vial, refill to 3ml using syringe.
Add 5 drops of Reagent B. Close vial with stopper and shake for a few seconds.
Remove stopper, add 0.15m of powder Reagent C with provided spoon. Close vial with stopper and shake for a few seconds.
Add Reagent D drop by drop, counting each drop while swirling the vial until the color changes from pink-violet to light blue. The color change should be stable for at least 30 seconds. Make note of the number of drops.
Subtract the number of drops in step 3 by the number of drops in step 7. Multiply the difference by 50. The resulting number is the amount of magnesium expressed in mg/lt (ppm).
Example: 30 drops minus 8 drops multiplied by 50 equals 1,100 mg/lt Magnesium.
