This article discusses the downsides of swimming pool ionizers. When finished, you can review the benefits or see how pool ionizers compare with saltwater pools.

Staining

Over the 20 years that pool ionizers have been on the market, staining has been the number one concern. And rightly so – if you spend tens of thousands of dollars on a pool, the last thing you want is unsightly stains.

Pool ionizers add minerals to the water to assist in controlling bacteria and algae in pools and spas by augmenting the bactericidal and algicidal activity of primary disinfectants (i.e., chlorine). Like anything dissolved in the water, they can become undissolved and collect on surfaces. Left unchecked, the undissolved minerals can stain.

Why does staining happen?

Over ionization

Some swimming pool ionizer systems are not adequately regulated. This could lead to ‘over ionization’ of the water where the amount of copper or other minerals is far higher than needed. For copper or copper-silver ionization to work, you only need 0.2 – 0.5 ppm of copper and about one-tenth of silver.

If the pool store says the ionizer needs to increase the water’s Total Dissolved Solids (TDS) by more than 500 for it to work, that is a sure sign that the system is not properly regulated, so you are better off finding a more sophisticated model.

Minerals are not chelated

Chelation (pronounced key-LAY-tion) is a molecular bond process that helps keep a compound dissolved in water. If the minerals are not adequately chelated, they tend to bond to surfaces rather than stay in the water, which can cause staining. Modern electronic mineral systems formulate the mineral electrodes such that the minerals are adequately chelated, but cheaper or older systems may not have this feature.

Water out of balance

A few conditions must be met for minerals to come out of solution. First, the mineral level has to be above 1 part per million (ppm). Second, the pH must be above 7.7, and/or the alkalinity must be above 120 ppm.

It’s essential to test your pool’s parameters every week or two to ensure balance. If you have a salt chlorinator, the chlorine generation process will constantly increase the pH, so it’s vital to test it regularly and adjust if necessary.

Contaminated source water

The water you fill your pool with may have a high mineral content. Testing your source water at a pool store before filling it is best. The water may contain iron, copper, or manganese at a high enough level to cause staining. It’s a good idea to fill your pool with a hose filter to ensure it’s as clean as possible.

Contaminated salt

Saltwater pools use a salt chlorinator to convert salt into liquid chlorine. They will work with most types of salt that you add to the pool. However, some salt is not refined correctly, so contaminants that dissolve in the water could be mixed in, leading to staining. It is best to buy your pool salt from a pool store to ensure it is properly refined.

Still need an oxidizer

Swimming pool ionizers allow you to reduce the chlorine and other chemicals required to maintain clean, clear water in your pool. However, the ionizer alone is not enough to do the entire job. Minerals assist in controlling bacteria and algae in pools and spas by augmenting the bactericidal and algicidal activity of primary disinfectants. Still, they do not oxidize organic matter such as lotions, sweat, and skin cells.

You need to use an ionizer along with an oxidizer. The most common oxidizer for pools is chlorine. Most ionizer manufacturers recommend reducing chlorine as the oxidizer (0.5 ppm to 1 ppm vs. one ppm to 3 ppm without an ionizer).

A weekly shock treatment for smaller pools will also address the oxidizing needs.

Ozone is a natural and fast-acting oxidizer fed into the pool through the plumbing. It is more automated than adding chlorine. However, there is an up-front cost, and regulations in most countries state that you still need a low residual of chlorine, even if you have both an ionizer and ozone. Also, ozone is short-lived, does not maintain a residual, and there is no way to test for it.

Can’t use stain remover / sequestering products

Pool stores often recommend stain and scale chemicals that remove iron, manganese, and other contaminants from the water. However, it would be best not to use these with a pool ionizer because they also neutralize the ‘good’ minerals added to the water. So, you must find another way to remove these contaminants from the water, such as a pre-filter that attaches to the hose.

The exception is if your copper level rises above 1ppm. In this case, you should bring it down, and you can use a sequestering chemical for this purpose.

You have to test the water for copper

You should test the copper level every two weeks with a pool ionizer. You must keep a copper test kit around or visit your pool store regularly. This adds one more step to your regular pool testing and maintenance.

You have to replace the cell every year or so

Pool ionizers house the minerals released into the water by a cell. This cell usually comprises two rods, either copper or a mix of copper, silver, and zinc. As the minerals are released into the water, the rods wear down and must be replaced every 6-12 months.

While the chemical savings offset the cost of the replacement cell, it is still an extra step that must be added to the regular maintenance.

Let us know if you think of other swimming pool ionizer problems. Otherwise, consider the benefits of pool ionizers or learn how saltwater pools and pool ionizers compare.