Depending on what you read online, you’ll either discover that a concrete pool with a salt water chlorination system is something you should avoid or is something that is perfectly reasonable to install.
Who to believe? I figured I should take a closer look at the facts and see where the truth lies.
A concrete pool needs to be resurfaced every 10 years and given its porous nature, salt from a chlorination system can damage concrete over time. A concrete pool needs to be scrubbed weekly to remove algae which fiberglass pools don’t experience and acid washing is also required every 3-5 years.
With that in mind, here are 5 reasons a concrete salt water pool isn’t a good idea and why another method of pool sanitation might be better if you have your heart set on a concrete design.
Concrete is porous and can be damaged by salt
It isn’t difficult to find conflicting information online from various pool builders as to their thoughts on whether or not concrete pools and salt water chlorination systems go together:
- Some concrete pool builders suggest that salt chlorination isn’t a good idea and will promote chlorine or ozone pool systems unless specifically asked to install a salt system.
- Other concrete pool builders will build them with a salt system and suggest that the talk over concrete and salt water being a dangerous combination is overblown.
- Other concrete pool builders will outright refuse to build a concrete pool with a salt system full stop.
The salt content in a salt water is typically kept between 2,700 ppm and 3,400 ppm which stands for parts per million. A typical chlorinator will enable you to keep salt around 3,200 ppm ideally so that it’s at the higher end of the range. This will ensure salt is high enough to enable the system to produce enough chlorine without taxing the salt cell.
While the salt content in a pool is relatively low it still means that the concrete is in constant contact with water and salt 24/7. Over time the effects of salt can cause pitting on concrete and lead to premature damage to the pool surface, requiring you to resurface it sooner than you might otherwise like.
Concrete allows algae to settle which increases cleaning time
Concrete is a porous surface meaning it naturally attracts and harbors algae and other undesirable contaminants. It’s such a problem that pool owners are advised to scrub the entire surface of their pool with a steel brush at least weekly to remove algae before it really sets in. At that point it can be very difficult to remove.
Algae can grow and multiply rapidly and during the pool season the last thing you want is to miss out on pool time due to a full grown algae bloom.
The more you neglect cleaning and the more algae is allowed to set in, the greater your chlorine and other chemical requirements will be. At a minimum this will increase your chemical usage and costs.
Concrete tends to require increased muriatic acid usage to bring pH down
The pH in any pool is critical to maintain to ensure proper water chemistry. Concrete is alkaline and will tend to increase the pH in a pool. Muriatic acid is typically used to lower pH in a pool so an increase in muriatic acid usage means more time and money spent on chemicals.
FYI, salt water chlorinators tend to increase the pH in a pool too so a concrete pool + salt water chlorination system can further exacerbate this problem.
Concrete pools tend to require resurfacing every 10 years
This is a major difference between concrete pools and other options: Every 10 – 15 years a concrete pool needs to be completely drained and resurfaced. This means emptying the pool of all water and letting it dry, prepping the surface by cleaning and priming it, doing the refinishing work, allowing it to dry again and then finally refilling the pool and balancing the water.
The cost?
Online research suggests that $10,000 – $20,000 is the expected range for the work to be done. And it’s typically not a job you’ll be able to do yourself and will need a professional to do. It’ll typically take up to a week to complete the work, weather permitting.
Concrete pools are much more expensive to maintain
Whereas a fiberglass pool typically has the lowest total 10 year maintenance cost and a vinyl pool is second cheapest, a typical concrete pool will be the most expensive to maintain. Online stats that I’ve seen suggest that during a 10 year period, a concrete pool will cost up to 7x as much as a fiberglass pool and around 2.5x as much as a vinyl liner pool to maintain.
A fiberglass pool has no liner to replace and typically has no significant maintenance work short of gelcoat refinishing which typically isn’t required on high quality, well maintained pools.
A vinyl liner pool does have a liner replacement to account for but it may not even occur in the 10 year period. A quality liner in a well-cared for pool may last longer. I’ve personally experienced this.
The major costs for a concrete pool involve the draining and resurfacing of the pool every 10-15 years and acid washing every 3-5 years. You may also expect to pay more for chemicals due to the downside of concrete’s porous nature which attracts algae which tends to kill chlorine, thus increasing sanitation requirements and possibly algaecide usage among other things.
Summary
Final considerations for a concrete pool:
- The general consensus is that if you want a salt water chlorination system, you’re better off with a vinyl liner or fiberglass option. If you want concrete, you’re better off using a regular chlorine system.
- Some people find the surface of a concrete pool hard on the feet and skin if you rub against it.
- Due to the nature of concrete curing, a concrete pool build may take 3-6 months with a great deal of manual and costly labor spread out as the concrete needs time to set.
- The up front cost of a concrete pool can be much higher than a liner or fiberglass installation. Online research suggests that a concrete pool typically costs $40,000 – $90,000 whereas a vinyl liner pool ranges from $30,000 – $50,000 and a fiberglass pool will cost $40,000 – $80,000.
- Ongoing maintenance and repair costs are higher than either liner or fiberglass pools.
- Having said that, a quality concrete pool can offer a very professional finish more so than a vinyl liner pool.
- Concrete pools can also be fully customizable more so than vinyl or fiberglass with swim up bars, beach entries and other features, at a cost of course.
Check out my page on vinyl vs fiberglass vs concrete pools to learn more about the differences between these three pool types.