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How to Fix Common Saltwater Pool Problems

Updated on August 28, 2017
Barack James profile image

Barack is a chemical engineer with a knack for pool chemistry. He has been in the pool maintenance industry for 8 years.

How to Maintain a Trouble-Free Saltwater Swimming Pool

Having a trouble-free saltwater swimming pool is not a rocket science; it’s all about monitoring (testing) chemicals used in the pool regularly (at least weekly) and maintenance of chlorine.

From my own experience (I've had a saltwater pool for more than five years now), the major problems (and what we'll discuss in this article) are low chlorine levels that cause cloudiness, low salinity, salt chlorinator maintenance, and corrosion issues.

How to Balance Chemicals in a Saltwater Pool

Freedom with any type of swimming pool begins with chemically-balanced water. To accurately test and adjust important chemicals such as pH, free chlorine, combined chlorine, total chlorine, total alkalinity, cyanuric acid, and bromine, I use a LaMotte ColorQ Pro 7 digital pool water test kit that takes a very accurate measurement for all the chemicals at once.

1. Test and Adjust Salt Concentration (Salinity)

  • A saltwater pool system will operate efficiently only when salt is in the right concentration.
  • Different chlorine generators will need different salinity levels, and this is the first thing you need to take in consideration before adding or reducing salt in your pool.
  • Chlorine generators will operate fine with salinity levels between 2500 and 3500 ppm. You must either test the salinity level before adjusting it or use a chlorine generator that monitors and displays the salinity reading.
  • Cooler geographic regions will experience reduced water conductivity, and if you are taking the reading of salinity from the generator, you may get a much lower and inaccurate reading, so you need to be extra careful not to add too much salt.
  • Make sure that you don’t add too much salt into the pool since the only way to reduce salinity is by draining the water and refilling with fresh water.
  • Test for salinity every week. Keep in mind that salt levels will be recycled during the process of chlorine production, and you may not need to add more unless the level falls way below the recommended range.
  • Here is salinity calculator that will guide you on the correct amount of salt to add to your pool to avoid excess salinity.

2. Test and Adjust pH levels

An ideal pH level is necessary to enable chlorine to function effectively and kill harmful bacteria. Ideally, the recommended levels for pH should be between 7.2 and 7.6, with the most ideal or optimal level of 7.4.

  • To reduce pH levels, you can use muriatic acid (liquid hydrochloric acid) or a dry acid such as sodium bisulphate.
  • To increase pH, you can use alkali such as soda ash: Ensure that you add these substances slowly in increments and allow the water to circulate for 4-6 hours before swimming.

3. Assess Free Available Chlorine

Monitor free chlorine levels by testing and adjusting on a regular basis. The recommended free chlorine levels should be between 2-5 ppm all the time, depending on the level of cyanuric acid in the pool as indicated in this chlorine/CYA chart.

Low salinity levels reduce free chlorine. If your free chlorine falls below the recommended levels, you need to measure salinity and increase it if it is below the recommended levels before even thinking of adding chlorine shock in the pool.

Very low salinity levels may bring down your available free chlorine to 0 ppm, which will almost certainly encourage algae to thrive.

Apart from low salinity levels, low free chlorine can be caused by ...

  1. Calcium buildup on the salt cell,
  2. An expired cell,
  3. Excess stabilizer (cyanuric acid), or
  4. Poor circulation.

If the salinity and everything mentioned above is just fine, but free chlorine is too low, this may be the result of heavy pool usage and you may need to add small amount of regular chlorine (or adjust your chlorine generator to produce more chlorine).

4. Monitor Total Alkalinity

Total alkalinity (TA) is as important as any other chemical reading. TA should be kept between 80 and 120 ppm to help keep pH stable, especially during the rainy season.

Very low total alkalinity may lead to:

  1. Corrosion,
  2. Metal staining,
  3. Calcium scaling, or
  4. Algae

On the other hand, high TA will cause cloudy or murky pool water and pH fluctuation.

To raise the total alkalinity, you can use sodium bicarbonate and hydrochloric acid. However, you should be careful when adding these reagents as they also have the same effect on pH. Use muriatic acid to lower it.

In most cases, balancing pH and TA is tricky and the only way to balance the two is by first reducing both chemicals using muriatic acid and then raising pH through aeration to get the correct balance.

5. Use a Stabilizer (Cyanuric Acid) Only If Necessary

If possible, always avoid stabilizers unless you have an outdoor pool in a hot and humid climate. Stabilizer (mainly cyanuric acid) is mainly used to help keep free chlorine stable by protecting it from exhaustion by sunlight and high water temperatures. The recommended levels of a stabilizer is between 40 and 80 ppm for saltwater pools.

The correct value of cyanuric may also differ with geographic locations, depending on temperature and how much sunlight is available during the day. This explains why a saltwater pool in Canada will need between 40 and 60 ppm and one in the USA may need up to 80 ppm of Cyanuric acid during the summer. Also, the amount of cyanuric acid you need will depend on the amount of free available chlorine. Very high levels of cyanuric acid will reduce the levels of free chlorine; you can use this CYA/Chlorine chart to determine the correct level to add at given level of free chlorine.

6. Determine Total Dissolved Solids (TDS)

This is the most ignored aspect pool water chemistry: The TDS in your pool should not exceed 1500 ppm.

The levels of TDS increases as chemicals are added and as organic matter dissolves in the water. If it drifts to the higher side, TDS significantly affects free chlorine levels and other chemicals and may cause cloudiness in the water.

The only way to reduce excess TDS is to drain and replace the water. Alternatively, you can increase the frequency of backwashing and cleaning your pool filter.

How to Clear a Cloudy Saltwater Pool

Just like a chlorine-based pool, saltwater pools turn cloudy when chemicals are not balanced. You need to ensure that all chemicals are balanced all the time to avoid cloudy water and the growth of algae. The major causes of cloudiness are chlorine, pH, total alkalinity, cyanuric acid, and calcium hardness.

To get rid of cloudiness, you will have to do a chlorine shock to raise the level of free chlorine (since the chlorine produced by the generator is not enough; a chlorine generator just assists you in maintaining the level of free chlorine). When the levels of chlorine and cyanuric acid are balanced and the water is clear, the chlorine generator will pick up from there and start producing chlorine to maintain the free chlorine levels.

How to Maintain a Saltwater Chlorine Generator (SWCG)

SWCG maintenance is all about cell cleaning and replacement, period: Chlorine production happens in the salt cell, and a defective cell will lead to less or no production of chlorine. You need to closely monitor the cell to ensure that there is no calcium buildup, which causes a low production of chlorine.

Ideally, even if there is no buildup, it is recommended to clean your cell at least every 6 to 12 months.

I use Hayward's AQR15 AquaRite Salt Chlorinator, which has a self-cleaning feature that makes it easy to clean any time. If you need more information, Hayward Chlorinators have a very inclusive guide on how to clean salt chlorinator turbo cell.

However, here is a quick, step-by-step general guide on how to clean a chlorine generator cell:

  1. Turn off all power.
  2. Remove the cell plugs.
  3. Use a screwdriver to remove the cell from the casing.
  4. Add sufficient muriatic acid to a bucket of water: Avoid too much acid, as it may reduce your cell life (about 6 oz of muriatic acid per quarter bucket of water is fine).
  5. Pour the solution into the cell and leave to soak for 5 to 10 minutes.
  6. Dispose of the acid solution and rinse the cell with a garden hose.
  7. Reinstall the cell.

Note: An expired salt cell might be the problem. The average lifespan of a salt cell is 3-5 years in most SWCGs, after which you need to replace the old cell with a new one that will produce sufficient chlorine.

Setting Appropriate Percentage to Run SWCG

Basically, all chlorine generators are have a percentage setting that controls how much chlorine they produce and how much time the pump runs to produce enough chlorine.

In some cases, you will be forced to increase the pump run time to allow for the production of sufficient chlorine when free chlorine is too low.

However, since the setting is a percentage of the pump runtime, you will have to readjust the percentage every time you change the pump runtime to get free chlorine from a low level to recommended levels.

Handling Corrosion/Metal Stains in Saltwater Pools

Saltwater often leads to faded surface and metal stains or corroded steel hardware parts.

Most salt chlorinator users, including myself, use zinc anode as part of the pool system to form stainless metal parts. Also known as a sacrificial zinc anode, it protects metals that come in contact with saltwater. Zinc anode also plays a very important role in preventing

  • plaster discoloration,
  • heater damage, and
  • black stains.

Zinc anode works by corroding or 'sacrificing' itself before any other metal part can be affected, like an underwater electrical system that can develop stains. You need to check on the anode at least once a year to ensure that it has not fully degraded.

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