Mineral Pools vs. Salt Water Pools
Salt water pools have been all the rage over the last decade. We’ll show you why mineral pools gives them a run for their money.
Saltwater pools have become popular over the past ten years. The main reason is the belief that salt water is a healthier alternative to chlorine-treated pools. This is a myth.
Saltwater pools use a device called a salt chlorinator to convert salt in the water into liquid chlorine. They have the same amount of chlorine as pools treated with chlorine directly, typically 1 ppm to 3 ppm.
Pool Ionizers release microscopic mineral ions into the water to assist in controlling bacteria and algae in pools and spas by augmenting the bactericidal and algicidal activity of primary disinfectants. This allows you to lower the chlorine concentration to 0.5 ppm. Health Canada says ionized pools or ‘mineral pools’ are the only pools where you can safely reduce the chlorine concentration.
This post compares saltwater pools with mineral pools that use a pool ionizer.
System Configurations
Salt Chlorinator
Saltwater pools use a device called a salt chlorinator. The salt chlorinator consists of a salt cell and a control box. The salt cell is plumbed into the pool plumbing on the line that returns filtered water to the pool.
The salt cell is connected to an electrical control box mounted near the cell and close to a power outlet.
Pool Ionizer
Pool ionizer configurations are very similar. A mineral cell is plumbed into the plumbing’s return line and connected to a control box.
The figure below illustrates the installation of a pool ionizer system. The blue tee houses the mineral cell threaded into its bottom. The mineral cell is then connected to a control box plugged into a regular wall outlet.
Maintenance
Salt Chlorinator
With a salt chlorinator, you add salt rather than chlorine to the pool. Several large bags of salt are required to kick off the chlorination process. The salt cell then converts the salt to liquid chlorine, creating a mini chlorine factory. Once the chlorine is used up, it is converted back into salt, so you will only need to top it up occasionally.
Most salt chlorinators also have a ‘burst’ function, like a shock, so you typically don’t need to use a chlorine or non-chlorine-based shock. However, you can use shock with a salt chlorinator if required.
Since liquid chlorine has a high pH, you must use a pH-balancing chemical to bring the pH down regularly. This is critical because chlorine does not work effectively with high pH. Salt chlorinator manufacturers and pool professionals typically recommend testing and adjusting pH every week.
Keeping the chlorinator settings low is essential if your pool will be covered for long. Chlorine burns off in the sun, so the chlorine level can get extremely high if your pool is covered, damaging your cover, liner, pool edges, and anything else in the water.
With salt chlorinators, it is essential to clean the salt cell regularly. The fins on the cell get scaled up over time and must be cleaned with muriatic acid. Generally, once per season is enough. However, if your water is really ‘hard,’ meaning there are many ‘dissolved solids’ or sediment, you must clean the salt cell more frequently.
Pool Ionizer
Pool ionizer systems add microscopic mineral ions to the water. It takes up to two weeks to build up the ions, which can be tedious initially. However, once they have reached the desired level, typically 0.2 ppm to 0.4 ppm, they are very stable, so you don’t have to test it very often. Also, modern pool ionizer controllers make it easy to ramp the ions up if you follow the directions.
Mineral pools also require a residual of 0.6 ppm of chlorine. This is used to burn up organic material that gets into the water from bathers (lotions, skin, hair, etc.) and the environment.
The easiest way to deliver chlorine in a mineral pool is with an inline chlorinator. The chlorinator hooks into your plumbing and provides a reservoir for adding several chlorine tablets simultaneously. There is a dial that allows you to set the chlorine output. Since the chlorine requirement is so low in a mineral pool, this can usually be set at 2 or 3 out of 10.
Mineral pools also require the occasional shock, usually after heavy usage or a rainstorm, which washes organic materials into the pool.
If you have ‘hard’ water or a large amount of dissolved material in the water, the mineral cell plates may get scaled up. This is usually not a problem because the microscopic ions can still get through. However, if there is a large amount of scale on the plates, you can file it off with a metal file.
Cost
Salt Chlorinator
Depending on the manufacturer, salt chlorinators cost between $500 and $2,000 to set up. The brand names Hayward and Pentair are at the higher end of this range.
If appropriately maintained, the cell that converts salt to chlorine will last 4 to 5 years. Depending on the manufacturer, replacement cells cost between $300 and $1,000.
Apart from the system, you will have to factor in the cost of chemicals. These are primarily salt, pH-balancing chemicals, and acid used to clean the salt cell. Since the salt is very stable in the water, you should not need to add much after the initial start-up. However, pH-balancing chemicals are used frequently.
Pool Ionizer
Depending on the manufacturer, pool ionizers cost between $200 and $2,000 to set up.
On a larger pool (above 25,000 gallons), you must replace your mineral cell every season. However, you can get two or more seasons out of a cell on a smaller pool—the replacement mineral cell costs $90 to $250.
Mineral pools also require a low residual of chlorine. The amount of chlorine needed depends on the size of your pool, usage, sun, rain, etc. We typically recommend adding one 3” tablet every week or two, less than half of what you need without an ionizer.
If you convert a chlorine-only pool to a mineral pool, a good rule of thumb is to divide last year’s chlorine cost in half. You might use less than that, but this is a reasonable estimate.
Risks
Salt Chlorinator
The most significant risk with salt chlorinators is corrosion to pool surfaces and equipment from the salt in the water. Some manufacturers of above-ground pools and equipment will void your warranty if you use a salt chlorinator, so it’s essential to check that before you buy this system.
If you are installing a new pool, it must be ‘bonded.’ This means that all of the metallic components, such as pumps, heaters, ladders, and light fixtures, are connected together with a wire. This helps divert the stray electrical currents generated by the chlorinator, which can cause corrosion.
If you have an older pool where the components are not bonded, you are likely to get rusting and corrosion on your equipment, which can be very costly to fix. Also, if your liner leaks and your inground pool uses steel panels, as most do, you could get rusting on the panels, which is extremely costly to fix.
Salt water can also be corrosive to stonework. If you have stone on your pool deck, you may need to apply a special sealant to prevent damage.
Pool Ionizer
The most significant risk with pool ionizers is discoloration of your pool lining from the minerals in the water. This is very rare with modern, computer-controlled systems. However, it is crucial to regularly test the mineral level in the water to ensure it is in the recommended range. It is also essential to test the pH regularly because when it goes out of the typical range, the minerals collect on surfaces more easily.
Benefits
Salt Chlorinator
With salt chlorinators, you don’t need to add chlorine to the water. The electronic chlorinator generates this for you by converting the salt in the water to liquid chlorine.
Continuous chlorine generation eliminates the chlorine byproducts when chlorine attacks organic matter. These byproducts cause the most chlorine smell in pools, so saltwater pools usually have less chlorine smell.
The salt in the water also gives it a soft feel.
Pool Ionizer
Pool ionizers add natural minerals to the water, which assist in controlling bacteria and algae in pools and spas by augmenting the bactericidal and algicidal activity of primary disinfectants. This allows you to reduce the chlorine concentration to around half of what you would need in a saltwater or traditional chlorine pool.
Mineral pools are usually less maintenance than chlorine or saltwater pools. This is because the minerals are always active in the water. Algae, in particular, usually gives the water a cloudy look. Pools with ionizers stay crystal clear all summer, even if you forget to add chlorine because the minerals always work.
Mineral pools usually stay within the typical pH range, so you don’t need to store harmful muriatic acid to balance pH.
To give the water a ‘softer’ feel, you can use a borate-based product that provides that salt-like feel without the salt.
Finally, with mineral pools, there is no risk of property damage or corrosion.
Read the Pool Ionizer Buyer’s Guide
Learn about the ClearBlue Mineral System
