Determinación de dureza del agua

Determinación de dureza del agua

Tiras reactivas para determinación de dureza del agua


Water Hardness can cause damage to the reverse osmosis (R.O.) System by forming scale and clogging up its membrane.

Most of municipal water or well water contains hardness between 10 to 15 grains per gallon of water. The hardness should be remove by a water softener to less than 1 grain/gallon (gpg) before the water enters into the reverse osmosis column for further purification.

The water softTM test strips has a dual detection range. The normal range covers 0,1,2,3,6,12 and 18 grains/gallon and is used for measuring hardness of the untreated water. The low levels test range covers 0, 0.2, 0.5 and1.0 grains/gallon or 0, 4, 8, 17 ppm. It is used for checking efficiency of water softener and to assure that there is not excess hardness entering the R.O. System.

Direction for use

Normal range Quantitative Test:

  1. Wet the strip in the water sample for one second.
  2. Shake the excess water gently.
  3. After 15 seconds, compare the strip color against the color blocks and determine the hardness from the numbers assigned to each color block.
  4. If the strip color falls between two color blocks, extrapolate the results.
  5. For water sample with hardness higher than 12 gpg. , more accurate result can be obtained y diluting the water sample with equal amount of deonized water and multiplying the result by 2.

Low range Hardness Test

By increasing the length of time the strip is in contact with the running water sample, the detection sensitivity of the WatersoftTM Test strip can be extended to near zero hardness.

  1. Hold the strip with the regent pad facing up against a slow stream of the test water for 15 seconds, or move the strip back and forth in the water sample for 15 seconds.
  2. INMEDIATLY, compare the strip color against the color blocks and find the equivalent low level water hardness from the following color blocks:
    3 grain color = 1.0 gpg or 17 ppm
    2 grain color = 0.5 gpg or 8 ppm
    1 grain color = 0.2 gpg or 4 ppm
    0 grain color = no hardness


The WatersoftTM test strip is sensitive to both calcium and magnesium ions. The strip color is a combined response of both ions and expressed as Total Hardness as CaCO3. Typical water hardness consists of calcium and magnesium in a ratio of 2:1. Other metal ions in the municipal or well water contribute very little to the Total hardness.

Quality control

For negative Control: Dip the strip in distilled o deonized water. The strip color should match the 0 gpg color.

For positive Control: Tap water or feed water can be used as a daily positive control. The results can be used for monitoring the consistency of the source water and efficacy of the water softener.

Optional Positive Control Solution: Control solution with hardness range of 180-250 ppm is also available in a dropper bottle. Apply one drop of the solution onto the reagent pad and shake off excess solution immediately. The strip should turn to a color close to 12 gpg hardness level. The solution can be purchased separately.


Store the strip at room temperature between 59F and 86 F (15-30C). Do not expose the strip under direct sun light. Do not refrigerate.


Contact Information

You can place your order by telephone, e-mail or fax. If you require a price quote for our products, please fill in our quotation form.

Customer service:
Tel: +54 223 482-7000 (and rollover lines) - 0800 666 3489