How Does A Saltwater Pool Work?


What Are The Most Expensive Saltwater Pool Repairs?

A saltwater pool systems works differently from an older style chlorine or bromine system that requires the use of more chemicals. While these systems use a pump and filtration system, saltwater pools have an additional component – the chlorinator cell and system – that turns regular water softener salt into chlorine to sanitize your pool and keep the water crystal clear.

So how does a saltwater pool work exactly and what does this extra chlorinator component mean for pool maintenance?

How Does A Saltwater Pool Work?

As mentioned, a saltwater chlorinated pool system works different from a chlorine or bromine in one key way:

Chlorine/Bromine pool: The chemical is added to the pool on a regular basis to sanitize it and keep the water crystal clear and sterile for swimming. As the chlorine dies over time and use, more chlorine or bromine is added to the system as required. These days chlorine is available in liquid, crystal, and puck format. The first two options are generally put directly into the pool whereas the puck is often added to the skimmer to dissolve over time.

Saltwater pool: A chlorinator system with a salt cell (a plastic device with electrified metal plates inside) converts the salt added to the pool into chlorine as the water is pumped through the system and passes through the cell.

Check out the diagram below and look at each aspect of the system. We’ll discuss all 10 stages below.

Swimming Pool Salt System.
This is a pretty good diagram of a typical salt water chlorination system. Your system might differ slightly and there is no pool heater in this example.

Here are the 10 aspects of the salt water chlorinator system as depicted above:

Gratings

Typically a hard plastic grate that allows overflow water to spill into it and then get put back into the pool system through the pump. We have a traditional concrete based pool with a vinyl pool liner so we don’t have gratings. Our neighbors across the road have a fiberglass pool and they have overflow gratings. You often see gratings at public pools where there is a lot of splashing and water sloshing around.

Surge Tank

A surge tank is used in conjunction with the gratings that you see above. The overflow water spills into this tank and eventually makes its way back in the pool, first through the chlorinator and the pump. Our pool doesn’t have have one since it has no gratings. Our neighbors with the fiberglass pool and gratings actually have an overflow bath basically. The overflow water spills into the bathtub (that’s what it looks like) and it then gets recycled back into the pool also through the chlorinator and pump.

Main Drain

The main drain draws water from the bottom of the pool through the pipes with help from the pump. Water is then returned through the chlorinator and pump, chlorine is regenerated and water returns back into the pool again.

Vacuum

Also known as a vacuum pipe. Although our pool doesn’t have one, your inground salt water pool may come with a vacuum pipe built in. This pipe helps to clear away water that may accumulate behind the vinyl pool cover and for other water removal tasks, too.

Water Pump

The water pump is what sucks water from the main drain and skimmer back into the filter and chlorinator and then pushes the newly filtered chlorinated water back into the pool through the return jets (referred to as Return Inlet #10 in the diagram above).

The pump also gets used for vacuuming the pool. In our case, we open the skimmer cover on the side of the pool, take the strainer out and push the end of the pool hose into the opening. The suction from the pump provides the vacuuming ability when cleaning the pool.

A standard swimming pool system with a black pump in the back, white piping for water flow and beige filtration system.
A standard swimming pool system with a black pump in the back, white piping for water flow and beige filtration system.

Filter Tank

Water that is returned from the pool gets pumped through the filter and cleaned and then gets sent through the chlorinator before returning to the pool. Several types of filters are common these days including:

Sand filter: The oldest type of filter and also the least effective filter type, it utilizes a special sand to filter your water. It requires backwashing to clean it which involves pumping water out of the pool to flush the filter when it becomes full which means higher water costs. Sand need to be replaced every 5-7 years. There are better options these days. You may also need to watch in your local area if you have regulations against dumping large amounts of pool water through the sewage system or similarly, using tap water in large amounts to fill a pool.

Cartridge filter: This is what we have in our pool so I’m most familiar with this type. We have a Sta-Rite System 3 cartridge filter. We find that the filter mediums – the 2 large filter drums that sit inside the filter – need to be replaced every 3 years or so. Whenever we get algae, it really screws up the filter mediums which then need to be rinsed off. This involves stopping the pool pump, releasing the filter pressure, unbuckling the fasteners, taking the lid off, removing the filter mediums and washing them off. It’s a 20 minute job.

Diatomaceous Earth (D.E.) Filter: This is widely regarded as the best type of filter currently available. While they offer the best filtration level (ie. they are able to filter out the smallest particles) it’s also the most expensive and work-intensive filter type. It requires backwashing every so often and washing and rinsing of the filter medium. Also, D.E. is recognized as a Group 3 carcinogen by the International Agency for Research on Cancer so care needs to be taken when using it and avoiding inhaling the medium is very important.

Flow Detector

The flow detector is a small indicator built inside the pipe that keeps an eye on the flow level of water passing through the pipe into the pump. Pumps that circulate liquid need a constant flow (water in the case of a pool) to pass through it otherwise an airlock will occur and the water flow will slow or stop. Also, the chlorinator cell must be kept from running with no water so a constant flow of water is required. Our Hayward system will automatically flip the chlorinator off if water flow runs low until the situation has been rectified. In this case, a light turns on to warn me that the flow is low.

Conversion Salt Cell to Chlorine

The salt cell is the key part of the salt water chlorinator system that converts salt to chlorine. Water passes through the cell which has electrified metal plates that turn the salt into sodium hypochlorite which is a safer form of chlorine that sanitizes the pool without the associated chlorine smell left on your skin and clothes. It’s easier on your eyes, too. With care, a salt cell may last 3-5 years before replacement is necessary.

Control Panel

The control panel is the box that you use to adjust various settings for your pool system. For us, our Hayward AquaRite system is inside a metal box that when opened, gives us access to the settings of the pump, chlorinator and even the heater. Depending on your system, the control panel could be smaller with less features or quite large for more expensive ones.

Return Inlet

Also known as the return or water jets. Our pool has two, which is typical: one in the shallow end and one in the deep end diagonally across from one another. All water that has already passed through the filter and chlorinator (and heater if you have one) returns to the pool cleaned and chlorinated through these jets. The pool should maintain a nice strong, consistent flow out of these jets to ensure peak pool performance.

Saltwater pools use the same salt you may already be using in your water softener. I use the exact same brand for both.
Saltwater pools use the same salt you may already be using in your water softener. I use the exact same brand for both.

As shown above, salt water pools use the same salt crystals or pellets that you use in your water softener. Your chlorinator system turns this salt into clean chlorine. Over time, salt usage is much, much cheaper, safer and cleaner than using and storing chlorine or bromine.

At the beginning of the season and often midway through the summer, I’ll dump an entire bag of salt into the deep end of the pool. It slowly dissolves and begins working its way through the main drain and through the chlorination system to produce chlorine.

Conclusion

  • How does a saltwater pool work? A saltwater chlorinator converts regular salt into chlorine to sanitize your pool water as opposed to using chemical chlorine or bromine.
  • While the up front costs of a saltwater system are more expensive, over time the cost of salt is much cheaper than chlorine/bromine usage with far less maintenance required.
  • Depending on how expensive and featured your chlorinator system is, you may have many benefits that make your work easier that help to maintain water chemistry automatically.
  • Learn more about the benefits of salt water over chemically-treated water for swimming pools with my post called Salt Water Pool System vs Chlorine vs Bromine.

Carl Mueller

I bought a home with a salt water pool in 2006 and soon realized the benefits over traditional chlorinated pools. On this website I'll discuss all the tips and tricks I've learned over the years. I'll also help you troubleshoot various problems with pools in general and ones specific to salt water pools that I've experienced personally!

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