One of the most common types of pool you’ll see in Florida homes is an inground concrete pool (related: inground pool cost guide). Homeowners prefer this type of pool because they can customize the pool’s size, shape, design, and depth.
I also had this made for my home because I wanted a specific look and liked the benefits that come with this pool (more about this later). After researching which design and material to get, I learned that it takes longer to construct and comes with a higher price to maintain.
If you prefer aesthetics over low-maintenance, like me, you probably got this pool as well. I’ll share with you some of the stuff I learned on how to take care of an inground concrete pool. But before we discuss its required maintenance, let’s find out more about the different types of a concrete pool. You'll also find the pros and cons of owning this pool as well as other pools and some of the common problems you’ll have to watch out for when you have an inground concrete pool.
What is an Inground Concrete Pool?
An inground concrete pool is one of the most popular types of pool homeowners get. It is created by digging a hole of the preferred size and shape into the ground and placing proper plumbing before putting a concrete foundation to contain the pool water. This concrete shell is attached with vinyl or fiberglass lining or smoothed with plaster (a mixture of cement and marble sand), tiles, pebbles, or special paint to remove the rough feel of concrete. If it’s not given this extra layer, this may cause scrapes and other injuries to the swimmers.
Similar to above-ground pools, inground concrete pools also have a filtration system. This keeps the pool clean and prevents dirt and other debris. But due to the nature of the materials used for this pool, it will require more maintenance.
One of those materials is concrete. There are two types of concrete used for this pool.
Shotcrete and Gunite
After the hole is dug, the pool is first fitted with a rebar or a grid with steel reinforcing rods, which is used to support the concrete. When concrete is sprayed on and around the rebar to form the foundation at high pressure, this is called shotcrete. The word is a mixture of shot and concrete because concrete is ‘shot’ on the surface.
There are two types of shotcrete, wet mix and dry mix. Wet mix is also called shotcrete while the dry mix is called gunite because it is applied using a gun-shaped device.
Shotcrete is a premade mixture of water and cement that is sprayed onto pools to form a concrete shell. It also contains sand, similar to gunite, but it is also mixed with pea gravel or other aggregates. This results in larger grained particles than gunite.
Gunite is a form of concrete that is created by mixing cement and sand. It is a popular choice for homeowners in the United States. This concrete is a durable structure and surface material, especially in warmer climates. It doesn’t require a liner and can withstand heavy impact.
Did you know?
Gunite is more expensive than vinyl pools in the north because of the cold weather. Because of the ice pressure, pools in the north require more concrete and steel.
Taking care of your Inground Concrete Pool
An inground concrete pool requires more attention and special care to keep it in good condition compared to other materials. You will need to regularly clean its surface and use chemicals to maintain water quality. For more details, here are some ways on how to maintain this type of pool.
Skim your Pool
When you have an outdoor pool, it is unavoidable for leaves, insects, and debris to appear in your pool. It’s important to remove these as soon as possible before it helps algae grow, cause circulation problems, or infects your pool. Use a long-handled skimmer to clean your pool’s surface or large debris that has fallen to the bottom of your pool.
Note: You can lessen the accumulation of debris in your pool by getting a pool cage.
Brush the Walls and Floor
You will need to loosen the algae, bacteria, and other debris stuck to the walls and floor of your pool. It is also important to clean these surfaces because they tend to harbor contaminants that may evolve in your pool. In the long run, not cleaning this will affect your pool water quality and visibility.
Use a hard bristle brush to clean the walls and attach it to a telescopic pole for the floor and other hard-to-reach places. Brush all possible areas in a circular motion to loosen all contaminants and prevent its growth.
Vacuum your Pool, Manually or Automatically
After brushing your pool, there will be loose debris floating around or settling at the bottom of your pool. Use a vacuum to remove these - you can manually vacuum it or invest in an expensive automatic pool vacuum.
Brush and vacuum your pool at least once a week, or more frequently, if it’s visibly dirty.
Balance the Water
It is very important to balance the water of your pool to protect the concrete and increase its lifespan. Take care of your pool water chemistry and get water test kits to know the current pH and calcium levels of your pool.
Never let the pH level go down because if the water is too acidic, it will corrode the concrete. So it shouldn’t go below 7.2 since the recommended pH level is between 7.2 and 7.6.
You should also check calcium hardness and make sure that the calcium level doesn’t get too low because the water will then get this mineral from the concrete walls instead. If calcium is leached off the walls, this will weaken and cause the wall to get rough and easily pitted.
Aside from prolonging your concrete pool’s lifespan, this will also prevent algae and keep your water clean and clear.
Since algae can easily thrive due to the nature of the concrete, you must apply algaecide to your pool. Once a week, use 3 ounces of algaecide for a 10,000-gallon pool - or it’s better to check the manufacturer’s instructions for the right amount.
You should also add chlorine twice a month to help sanitize the pool water. Check the manufacturer’s instructions as well to find out how much you should use. Make sure to pour it in the outer edge of the pool and apply it evenly. If it’s poured in one spot, it won’t dilute properly. Test your water after adding this chemical to check if the chlorine level is around 3 parts per million (ppm), which is the recommended and safe level.
Always Clean and Check your Filter
Because of the nature of the concrete material and the alkaloids and metals from the plaster liner, your pool will require heavier filtration. Run the filtration system for around 8 hours a day to ensure proper circulation. This will maximize your filter so you should make sure that the filter is always clean and working.
Sometimes regular cleaning is not enough to clean your pool. The time will come that you will need to ask a professional to acid wash your pool or you can do it for yourself (if you're confident). One reason people get an acid wash is after an algae infestation, which often results in stains. Acid washing a stained pool will remove a thin layer of plaster or concrete to show a new and fresh layer. Because the foundation gets thinner, this method must not be done frequently. Only opt for acid washing when the stains or damage cannot be removed by other methods.
Every 7 to 10 years, your concrete pool needs to be resurfaced. It has to be done more frequently for homes in colder climates.
It is important to resurface to remove stains caused by high levels of copper, iron, and magnesium, calcium hardness, dissolved solids low pH, and total alkalinity, calcium hardness, since these may be harmful to swimmers if left for too long.
Note: Some pool manufacturers give lifetime warranty for the structure, but it may not apply to the finish. Make sure to get a surface warranty.
Before getting a professional to do acid washing or resurfacing, you must first drain your pool. Find out how to drain your inground concrete pool here.
Common Problems for Concrete Pools
Aside from cleaning and maintaining your pool, there are also some problems that you’ll have to watch out for.
Water chemical imbalance: Concrete has microscopic pores that can host bacteria, algae and other contaminants that may affect the quality of your pool water. As these can build-up, it may threaten the balance of your water chemistry. You will need to use better filtration systems and more chemicals to maintain the pH levels. That’s why it is important to also clean the surface of your pool and scrub the walls to remove debris. If you have a tiled pool, you may have an easier time with this problem that those who have a plastered pool.
Concrete erosion: It’s annoying because you will need to use more chemicals, but at the same time, you have to know how much. If you bombard it with too much, this will cause the concrete to erode (whether it is painted, tiled, or plastered). So even if it’s tempting to sterilize the whole pool until deep in the foundation - don’t.
Foundation surface becomes rougher: Even if you regularly clean and maintain your pool and add the right amount of chemicals, the time will come that the surface of the foundation will wear down, which will roughen the surface. This could injure or hurt your swimmers when left untreated. It gets rougher with age, so make sure to get it resurfaced.
Concrete cracking: Another unavoidable problem you will face with concrete pools are cracks. It is normal because this material is rigid, making it prone to cracking. It can also happen due to seismic activity, the soil shifting, or erosion that affected your pool’s support. Aside from leaks, this can potentially harm swimmers as well. It is expensive and difficult to repair, especially when it has affected the entire foundation of your pool. Make sure to seal a small crack as soon as you see one since it can get bigger if left unchecked. You may need to ask a professional to resurface your pool to repair large cracks.
Benefits and Drawbacks of an Inground Concrete Pool (and other types)
This pool comes with disadvantages but the benefits outweigh the drawbacks.
If you want to know the pros and cons of the other types, here is what I learned about vinyl and fiberglass.