Tropic Marin NP-Standard

Tropic Marin NP Standard is a laboratory-made reference solution for verifying the effectiveness of NO3 and PO4 test kits. If the test kits are no longer effective due to incorrect storage conditions or high/low temperatures, you can calculate a correction factor that should be taken into account when you use the tests.

Instructions for use:

Follow the instructions given in the test kit's manual!

Checking the effectiveness of reagents:

1. Use either reverse osmosis water or demineralised water. Fill the cuvette with the required amount of water. Attach the blue tip to the syringe included in the pack and measure out the required amount of NP Standard from the bottle:

► For 5 ml water sample = 0.13 ml Tropic Marin NP Standard

► For 10 ml water sample = 0.26 ml Tropic Marin NP Standard

► For 15 ml water sample = 0.39 ml Tropic Marin NP Standard

2. Add the required amount of NP Standard to the water sample. Now you can carry out the measurement with the test and determine the measured value M.

3. If you add NP Standard to the water, the target value S should be 2 mg/L of nitrate or 0.2 mg/L of phosphate. If the measured value M matches the target value S, the test is still effective and can be used as usual. If the measured value M deviates from the target value S by 50-75%, you should no longer use the test.

Correction factor K:

If the deviation between measured value M and target value S is less than 50-75%, you can calculate a correction factor K to continue using the test. Use the formula: K = S / M.

To continue using the test kit and find out the correct value W, you will need to multiply all future readings by the correction factor K.

Note: Check your test kits every 2-4 weeks!