Danny’s Pool and Spa Combo – USA

Pool and Spa

Danny first got in touch with me back in May of 2021. What he was looking to do was to build a Pool and a Hot Tub with an overflow.

For regular readers of the blog or for those of you that watch my videos on YouTube will know that I like to keep the waters separate in pools and spas. Danny was very clear on what he wanted to do.

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The remit for Danny’s build was that he wanted the water to be circulated through the spa, creating a waterfall overflow into his pool. He was going to use the pool heating and filtration system to do this but wanted me to design him a system that would allow him to have separate control of the hot tub jets.

First things first, he needed a plan. This was a custom project (you can read more about these here) but with the right plan in place, Danny was heading in the right direction from the start.

Enter the Pool Builder

There are two parts to this build, the pool itself and the hot tub. What I have certainly found over the years is that pool builders don’t like to do hot tubs. Or, if they do, they often do them wrong!

In Danny’s case, I will share a portion of an email that he sent to me. Basically, the pool builder only dealt in steel pools with liners so wanted to do the same for the hot tub – this was not going to work! You can’t get the jets you need for liners and they are a total pain to do where hot tubs are concerned – fine for a pool of course, just not a tub.

Extract from Danny –

Pool builders.  When I suggested to my pool builder that he build something liek you did  he was like “no way. I don’t do that.  I only do steel walls with vinyl liners OR get drop the fiber glass ones in the hole and connect the suction line, return line and blower line.  So I showed him a picture of steel wall hot tub (below) and asked him “So can you do this?”   “Of course” he said.    So then I said. “Well If I hire a mason or you hire a mason to build the concrete shell it is exactly the same thing.  If the pool builder or the owner isn’t handy they also have to do the tile finish or find someone.  But you get the idea.  Now he’s like “ok let’s do it.”    I think once a couple pool builders start doing it word will spread to owners or other pool builders.  Yes I understand after a pool builder does it once they might not be a return customer but I think it will catch on and owners will be requesting their pool builders to contact you if the owners themselves can’t do it.

As you can see, Danny was clear on what he wanted – and just needed to find the right people to do it.

Let’s Get Digging!

As with any pool or hot tub build, you have to clear the area so this is the initial picture from Danny of his build. Quite the project as you can see.

Pool Spa Combo Start

It always surprises me just how much correspondence I actually have with my customers. In going back through my records to find the pictures and the videos that Danny has sent for this article, there was dozens and dozens of emails spanning over 12 months. Quite incredible really.

Start with the Pool

The plan that Danny and his contractors had was to start with the pool. The pool was going to be a steel framed in ground pool with a liner. Quite straight forward to do but I do recommend getting someone in to do the liner part.

Pool liners can be notoriously difficult to fit so should really be done by a pool professional or at least someone that has experience in them. I wouldn’t suggest trying to do a liner pool as a complete DIY project without assistance.

And now the Hot Tub

With the pool in place, it was time for Danny and the team to start work on the block built hot tub. He was going to make this from hollow CMU blocks with a rebar internal structure. This is a popular method for a DIYer.

The first thing that he did was lay a concrete base. With the concrete base in place, it was time to start to lay the blocks.


It didn’t take the brick layers too long to put the external and internal structure together for Danny.

The next steps were to core the holes for the Gunite bodies to be fitted. It is pretty straight forward process but does take a bit of time. My recommendation here is that you hire a core drill, much easier and quicker than doing it yourself (like I did) with a regular hand drill.

Core Holes

Danny then fitted the 2.5” pipes through the walls and then sealed around them. He also added a seal on the walls to add additional water proofing to the structure.

External Pipe Work

With the Gunite Bodies in place, it was time for Danny to fit the exterior pipe work. What he did which I think works well was that he actually fitted a sheet of insulation before he fitted the actual plumbing. Then it was time to put the 1.5” air lines and the 2” water lines around the tub to feed the 9 jets.

With the plumbing in place, Danny then needed to fill in the seat void which he did with a mixture of concrete and block and then he has used a product called ‘Hydraflex” which is pink in nature to seal all of the concrete after it has been rendered internally. Again, this just adds another layer of waterproofing to the structure. It is certainly starting to take shape as you can see in the picture below.

At this point, Danny needed to some work on the exterior of the structre and as you can see, he has used a waterproofer on the exterior structure too.

The next stage for Danny was to backfill around his pool and get ready for the concrete pour.

Bring on the Tiles

How good do these look. Danny has opted for a circular mosaic tile which looks absolutely fantastic.

Danny has also put in a second skin of blockwork to cover up the pipes and he has put coping onto the top of the hot tub as well. This is really starting to take shape. I think it was at this point his email to me read something along the lines of this is taking ages!

Well worth the wait Danny.

With the tiles done, it was time for Danny to actually hook up the plumbing and test the pool overflow.

Fast forward quite a few weeks, the area around the pool has been finished, the exterior of the hot tub has been cladded and this is one fantastic looking project. Really well done Danny, this is beautiful work. Thanks for the kind words too!

Thought I would celebrate with you that I got the final connection hooked up today.  Wanted to also say thanks as I wouldn’t have been able to do this without you.

It took extra long because of pool contractor delays with the regular pool and a number of other bumps in the road.


Pool and Spa

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Post Project Questions

Following the completion of Danny’s build, I have been asked a number of questions that I thought that I should include on the page.

How much is a pool and hot tub combo?

The cost of a pool and hot tub combo can vary widely depending on various factors including the type of pool and hot tub, their size, features, materials, location, and additional installations. Here are some general cost considerations:

  1. Type of Pool: The type of pool you choose, whether it’s an in-ground pool or an above-ground pool, will significantly impact the cost. In-ground pools tend to be more expensive.

  2. Hot Tub Type: Hot tubs come in various types, such as portable, above-ground, in-ground, and swim spas. Each has a different price range.

  3. Size: The size of the pool and hot tub matters. Larger pools and hot tubs will generally cost more.

  4. Features: Additional features like lighting, heating systems, jets, and water features can increase the cost.

  5. Materials: The materials used for the pool and hot tub, as well as the surrounding area, can affect the price. For example, concrete pools tend to be more expensive than vinyl or fiberglass pools.

  6. Location: The cost may vary depending on where you live, as labor and material costs can differ by region.

  7. Installation: Installation costs, including excavation, plumbing, electrical work, and landscaping, can add to the total expense.

  8. Accessories: Don’t forget to budget for accessories like pool covers, maintenance equipment, and water treatment systems.

  9. Maintenance and Operating Costs: Factor in ongoing costs for water treatment, heating, and maintenance, as well as any increased utility bills.

If you get someone to build this for you, it is also going to cost a hell of a lot more than if you do it yourself. A Pool builder would charge $80K+ for the kind of setup that Danny has.

If you do it yourself, you might get that cost down below the $30K mark which is quite the saving.

How does a pool and hot tub combo work?

A pool and hot tub combo typically work as separate water bodies that share some common equipment and can be used independently or together. Here’s how it generally works:

1. Separate Water Circulation: A pool and a hot tub have their separate water circulation systems. Each has its own pump, filter, and heating system. The pool’s system is designed to maintain the pool water, while the hot tub’s system does the same for the hot tub.

2. Shared Heating: In most pool and hot tub combos, there is a shared heating system. This means that a single heater can be used to heat both the pool and the hot tub. The water is circulated through the heater to achieve the desired temperature for each. The shared heating system allows you to save on energy costs compared to having two separate heating systems.

3. Water Quality and Filtration: Both the pool and hot tub have their water treatment and filtration systems. These systems help maintain water quality by removing debris, bacteria, and other impurities. Chlorine or other water sanitizers are typically used to disinfect the water.

4. Water Features: Some pool and hot tub combos have water features like waterfalls or fountains that can be shared between the two. These features can enhance the aesthetics and create a more enjoyable environment.

5. Water Levels: The water level in the hot tub is typically higher than that in the pool. This allows the hot tub water to overflow into the pool, creating a seamless transition between the two. The pool and hot tub usually have separate drains to control the water levels.

6. Independent Use: You can use the pool and hot tub independently of each other. If you want to relax in the hot tub, you can do so without affecting the pool. Similarly, you can swim or play in the pool without altering the hot tub’s water.

7. Pool and Spa Mode: Some combo systems come with a “pool and spa” mode. When this mode is activated, the heater prioritizes heating the hot tub. Once the hot tub reaches the desired temperature, the excess heat can be diverted to the pool. This allows you to maintain a comfortable hot tub temperature while maximizing energy efficiency.

Overall, a pool and hot tub combo offers flexibility, allowing you to enjoy the benefits of both a pool for exercise and cooling off and a hot tub for relaxation and hydrotherapy. The shared equipment and heating system make it a convenient and cost-effective option for homeowners who want the best of both worlds.

How do I keep my hot tub heated but not my pool in a pool hot tub combo?

Keeping your hot tub heated while not heating your pool in a pool and hot tub combo primarily depends on the design and settings of your specific system. Here are some general steps to achieve this:

1. Check Your System Design:

  • Determine whether your pool and hot tub share a heating system or if they have separate systems. In most combo setups, they share a heating system. If they share a system, it’s more challenging to heat one without the other. If they have separate systems, you have more control.

2. Invest in a Separate Hot Tub Heater (if Possible):

  • If you have separate systems, consider installing a dedicated hot tub heater. This allows you to control the hot tub’s temperature independently.

3. Use a Pool Cover:

  • A high-quality pool cover can help retain the pool’s temperature and reduce heat loss. When the pool cover is on, it will slow down the cooling of the pool, even if the heating system is running. This way, you can focus the heating efforts on the hot tub.

4. Set Pool Heating to a Lower Temperature:

  • If you share a heating system and your pool has a lower desired temperature than the hot tub, you can set the pool’s heating temperature to the lower end of the range. The heater will primarily heat the pool but will still maintain the hot tub’s temperature, even if it’s higher.

5. Use a Timer or Programmable Thermostat:

  • If your pool and hot tub share a heating system, you can use a timer or programmable thermostat to control when the heating system operates. Program the system to heat during times when you want the pool heated, and then turn it off when you want to focus on the hot tub. This way, you can avoid unnecessary heating of the pool.

6. Use a Pool and Spa Mode (if available):

  • Some combo systems have a “pool and spa” mode, allowing you to prioritize heating the hot tub first. Once the hot tub reaches the desired temperature, the excess heat can be diverted to the pool.

What are the design considerations for a pool and hot tub combo?

Combining a swimming pool and a hot tub can create a luxurious and versatile backyard oasis. However, there are several design considerations to ensure that the pool and hot tub complement each other and provide an enjoyable experience for all users.

Space and Layout:

  • Available space: Determine the available space in your backyard to accommodate both the pool and hot tub. Consider the size of each feature, as well as any additional landscaping or decking elements.

  • Layout and proximity: Plan the layout of the pool and hot tub to maximize space utilization and create a cohesive design. Consider the proximity of the two features for ease of access and visual appeal.

  • Traffic flow: Ensure that the placement of the pool and hot tub allows for smooth traffic flow around the backyard, avoiding congestion and potential hazards.

Shape and Design:

  • Pool and hot tub shapes: Choose complementary shapes for the pool and hot tub that blend well with the overall design aesthetic. Consider rectangular, oval, or kidney-shaped options.

  • Elevation and transitions: Decide whether the pool and hot tub will be at the same level or have different elevations. Create smooth transitions between the two features using steps or ramps.

  • Water features: Consider incorporating water features, such as waterfalls or fountains, to enhance the visual appeal and add ambiance to the pool and hot tub area.

Materials and Finishes:

  • Compatible materials: Select materials for the pool and hot tub that are compatible with each other and complement the surrounding landscape. Consider materials like concrete, tile, or stone.

  • Surface finishes: Choose surface finishes for the pool and hot tub that are durable, slip-resistant, and aesthetically pleasing. Consider options like polished concrete, textured tile, or natural stone.

  • Lighting: Incorporate appropriate lighting to enhance the ambiance of the pool and hot tub area. Consider underwater lighting, poolside fixtures, and landscape lighting.

Additional Considerations:

  • Privacy and screening: Ensure that the pool and hot tub area have adequate privacy from neighbors or passersby. Consider planting trees, shrubs, or installing privacy screens.

  • Accessibility: Design the pool and hot tub area to be accessible to all users, including those with disabilities. Consider features like ramps, handrails, and accessible steps.

  • Maintenance and upkeep: Plan for the ongoing maintenance and upkeep of both the pool and hot tub. Consider the cost of chemicals, cleaning, and repairs.

  • Local regulations: Check with local regulations regarding pool and hot tub installation, fencing requirements, and safety measures.

By carefully considering these design factors, you can create a stunning and functional pool and hot tub combination that will enhance your backyard and provide years of enjoyment.

What are the sanitation options for a pool and hot tub combo?

Maintaining proper sanitation is crucial for a safe and enjoyable pool and hot tub experience. Several sanitation options are available for pool and hot tub combos, each with its own advantages and considerations.

Chlorine: Chlorine is the most common and widely used sanitizer for pools and hot tubs. It is effective in killing bacteria, algae, and viruses. However, chlorine can be harsh on skin and eyes, and it can produce unpleasant odors if not properly balanced.

Bromine: Bromine is a similar sanitizer to chlorine but is less harsh and less likely to cause skin irritation. It is also more stable at higher temperatures, making it a better choice for hot tubs. However, bromine is more expensive than chlorine and can be more difficult to find.

Salt Chlorination: Salt chlorination systems convert salt into chlorine through electrolysis, providing a continuous supply of sanitizer. This method is considered more natural and less harsh than traditional chlorine addition. However, salt chlorination systems require a specialized salt generator and may be more expensive upfront.

Ozone: Ozone is a powerful sanitizer that is also environmentally friendly. It breaks down quickly in water, leaving no residual chemicals. However, ozone systems can be more expensive than other sanitation options and may require additional equipment.

Ultraviolet (UV) Light: UV light kills microorganisms by disrupting their DNA. UV systems are often used in conjunction with other sanitizers to provide additional protection. However, UV systems may be less effective against certain types of microorganisms and require regular maintenance of the UV bulbs.

Natural Sanitizers: Natural sanitizers, such as enzymes and mineral-based systems, are becoming increasingly popular as alternatives to chlorine and bromine. These sanitizers are often marketed as being more gentle on skin and eyes and more environmentally friendly. However, natural sanitizers may not be as effective as traditional chemical sanitizers and may require more frequent maintenance.

Considerations for Pool and Hot Tub Combos:

When choosing a sanitation option for a pool and hot tub combo, consider the following factors:

  • Size and volume of the pool and hot tub: Larger pools and hot tubs will require more sanitizer than smaller ones.

  • Usage frequency: The frequency of pool and hot tub use will influence the amount of sanitizer needed.

  • Personal preferences: Consider your personal preferences for skin sensitivity, odor, and environmental impact.

  • Cost: Different sanitation options have varying costs upfront and in terms of ongoing maintenance.



Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

Thanks - Andi


Hi, Andi here. I own Buildahottub.com and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Today, I've helped over 1000 DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi

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