How to test for Salt using a Hydrometer

Hydrometer Cylinder and Samples

Unless your pool has a salt water generator (SWG), it is unnecessary to test for salt levels in your pool. SWGs consume the salt in the pool to turn into free chlorine, meaning that daily addition of chlorine is unnecessary. Most SWGs have a broad range of operation (the difference between the “too little salt” point and the “too much salt” point), but it’s important to keep the salt within that range. Too little salt means your SWG cannot produce enough chlorine for your pool, too much salt and you can risk damaging your SWG.

The instructions on the sides of our kits are simplified reminders of the procedure for advanced users. These are the extended instructions for the Salt Level Test Kit, that give you all the needed details on how to test your pool for salt levels.

To ensure your kit is working, we have included a salt standard of 4000ppm. When you use this standard instead of pool water, your test should read 4000ppm. It is not necessary to use this at all, however it can provide reassurance if you are new to testing, or you think you may have damaged your hydrometer.

  1. Rinse the salt hydrometer and measuring cylinder with pool water
  2. Using the measuring cylinder, obtain a sample of pool water (~210mL). Make sure the sample is from at least elbow deep in the water.
  3. Place the measuring cylinder on a level and stable surface.
  4. Place the salt hydrometer into the measuring cylinder. Tap and rotate the hydrometer to dislodge any tiny air bubbles. Be careful not to break the thin stem while handling the hydrometer.
  5. Note: Air bubbles that settle on the hydrometer will cause an artificially high reading of your salt levels.
  6. The water level on the salt hydrometer stem will indicate the salt level in parts per million (ppm).
  7. Note: The hydrometer is has been calibrated using water that is 25oC. If the water temperature is cooler or hotter than this, the reading will need to be adjusted according to the table to the right.
  8. Rinse the hydrometer with tap water, and then store in a cool, dry, place. Do NOT leave this hydrometer on its side. Store upright to maintain the shape of the stem.

 

Temperature Correction Chart:

Temperature Correction
21oC subtract 1600ppm
22oC subtract 1200ppm
23oC subtract 800ppm
24oC subtract 400ppm
25oC no correction
26oC add 400ppm
27oC add 800ppm
28oC add 1200ppm
29oC add 1600ppm

 

Want a printable version of these instructions? We have you covered!

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2 thoughts on “How to test for Salt using a Hydrometer

  1. Steve says:

    I tried to get a narrow range hydrometer over a year ago but failed, I can’t wait to get my hands on one. Salt is one parameter that the pool shops around me record quite poorly, even with their expensive conductance meters, often up to 1000ppm out, which can be as much as two bags of salt and potentially damage a chlorinator.

    Thank you so much Clear Choice Labs, your customer service is second to none and my pool has never looked better.

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