Hot Tub DIY From A Stock Tank Pool

Stock tank pool lovers, unite! Today we have a tutorial just for YOU and it involves turning that beloved tiny pool into a hot tub. We've been brainstorming this project for well over a year, and in the dead of winter we finally made it happen!

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Guys, you cannot imagine the trial and error we have been through to bring you this DIY today!! There is not enough time in the day for me to explain it to you. We did, however, film a behind the scenes video that we will share with you very soon.

DISCLAIMER- We are not electricians or plumbers or contracts. We are not experts of any kinds. This project involves electricity and water, so please use extreme caution. Do this project at your own risk.

** The post contains affiliate links and I will be compensated if you make a purchase after clicking on one of my links. 

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    Last winter I started doing research on how to turn our stock tank pool into a hot tub so we could extend the life of the pool and have something fun to do outside in the winter. After TONS of research, all we had found were a bunch of people either raising their pool about 8 degrees or wood firing their hot tub. Raising water 8 degrees would be extremely insignificant and wood firing takes a lot of hands-on work to heat up the water. Especially with our 700 gallon tank. I was overwhelmed with the lack of information, so we decided to put the project off until the end of the next summer.

    When the time finally came around, I did more research. The results were the same. I finally found this video that was a game changer for us! I was fired up to get this project going. I figured out exactly what I needed to make the project happen, and over 5 months gathered what we needed, talked to people at Home Depot, learned about electricity and plumbing, etc. I say all this so you will understand all the work that has gone into this. We hope that by documenting this project, you can make the same thing happen in just a day or 2!

    And since I know you're going to ask- we have successfully raised our pool 59 degrees. The temperature outside has ranged from 30 degrees Fahrenheit to 55 degrees in the process. It did take 3 days to get the temperature to a desired temperature. This is where I'm going to tell you that this isn't a perfect hot tub. This is mostly ideal in the spring or fall when the temperatures have dropped and you want to extend the time you are able to use your pool. There are also lots of things we could do to help the pool heat up faster and retain heat better. We are just happy to have successfully heated the stock tank pool and raise it 50 degrees. Without question we will be working to improve this design.

    The first thing we need to talk about is what you need to make this project happen. As you may have realized already, this is a project that is building onto our first DIY Stock Tank Pool project. So you'll need to have completed that first. I'm going to list all the supplies you need for this project below, but be warned- the list may seem overwhelming. I'm going to link every product so you can easily access the pieces I am talking about.

    For this project, you will need:
    - Water Heater Element(s)
    - Digital Thermostat
    - Electrical Tape
    - Extension Cord(s)
    - Wire strippers
    - Plug extender
    - 1.5" Pool Replacement Hose
    - 2' piece of 2" PVC pipe
    - 2 x PVC Reducer Bushing (2" x 1")
    - 2 x 2" PVC Double Sanitary Tee
    - 2 x PVC Male Reducer Adapter (2" x 1-1/2"2)
    - 2 x 2" PVC Caps
    - PVC Cement
    - 2 x Reducing Washer (1-1/2" x 1-1/4")
    - 4 x Rubber Washers (3/4 x 2-1/4 x 1/8)
    - 2 x Machine Bushing (1-1/2 x 2-1/4 x 14 gauge)
    - Silicone

    Before we get started you need to figure out some things for your specific hot tub. How many gallons is your stock tank? Ours is 700 gallons. Since our is so big, we are using two heating elements. If you have a smaller pool, say 200 gallons, you could probably get away with just one heating element. If you have a 400 gallon pool, I'd say to stick with 2 heating elements. Your pool will heat up almost twice as fast as ours does. The only thing about using 2 heating elements is that you will need two outlets on separate circuits. You can plug up your pool pump and one heating element into one outlet with no problem. And if you have the ability to use 3 heating elements and you have the 700 gallon pool we have, go for it. It will only help you heat your pool faster.

    And there is one more decision you have to make… I promise the decision part is almost over! We just need to make sure you are tailoring this to you specifically. There are two ways to keep track of your water temperature and the heaters. This first is to plug everything up to run and keep an eye on the temperature with a submerged thermometer. We have found that these aren't exact, but they are close enough with their accuracy. The second option is to get an electric thermostat that keeps track of the water temperature and turns the pump and heaters on when the water gets too cool. It also stops the water from overheating. This option is great for smaller pools where you do run the risk of the water getting too hot. It's also a great option if you want to keep the hot tub warn over a long period of time. The only problem is that you can only hook up one heating element.

    Here is our video tutorial below!

    Make sure you download our free printable hot tub manual to make this project a little easier! Let's get started.

    Step 1. To start, you will need to make some cuts on your PVC pipe. You will need 4 pieces that about 3 inches long and the excess will be your 5th piece.

    Step 2. Assemble all the PVC pieces to dry fit. We want to make sure that everything fits in the right way before glueing it together.

    Step 3. Once the dry fit is complete, start cementing the PVC together at each connection.

    Step 4. Remove the rubber gasket that comes with the heating element and replace with the bigger gasket.

    Step 5. Coat the threads of the heating element in silicone and then thread it into the correct PVC connection.

    Step 6. Cut the extension cords close to the outlet end. Strip off the jacket to expose the wires, without cutting the wires.

    Step 7. Attach each of the wires to the ends of the heating element. They can be attached in any way, as long as there is only one wire per screw-in.

    Step 8. Let the PVC cement cure for at least 4 hours and the silicone for at least. If you are leaving the heater outside to cure, wait at least 24 hours.

    Step 9. Connect the new hose to one one end of your heater with 2 rubber washers x 1 machine bushing sandwiched in between. This will help create a better seal so there is no leakage. I couldn't find the perfect sized rubber washer so I took this one and cut the inside circle wider to match the width of the machine bushing piece.

    Step 10. Plug your heating element and pump into to the electric thermostat using a plug extender.

    Step 11. Connect the thermostat pieces and place the silver end into the water. Follow the instructions on how to create your own settings. Plug the electric thermostat in and double check that the pump is actually running. Then wait for the pool to heat up!

    Things to note:
    1. You must have the pump running if the heaters are turned on. If the pump isn't running, the water will boil and develop a lot of pressure that (from experience) can push the heating elements out of their place completely. The sealant can also get too hot and melt, which opens the seal up. So make sure the pump and heaters run simultaneously.
    2. You must have an outlet on its own circuit. If you are using two heating elements you will will need two outlets on their own circuit to make sure you aren't tripping out the circuits with everything plugged in.
    3. You need to keep the electric thermostat in a place where it can be safe from rain water. Our stock tank pool has a bench so it's rather easy to keep things dry with our pool cover or a simple tarp.

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      Please keep in mind that we are just two ladies who love to do DIYs and home projects. There is probably a better way to make this. But this is what we could come up with in our brains and with the resources we had. And we are really dang proud of this project. We were working on basically nothing. And to our knowledge and extensive research on the internet- no one has done what we have done here. We're freaking stock tank pool hot tub pioneers!

      Thank you so much for joining us on this adventure! If you are wanting to complete this project at some point, make sure you pin an image from this blog post for later. Don't forget to check out how we DIYed our stock tank pool.

      Happy DIYing!

      -Savannah & Casey

      P.S. Check out our new website- Stock Tank Pool Authority. We have a TON of resources all in one great place!


      1. how's this working out for you? I've been trying to convince my wife of this venture.

      2. I am curious if anyone knows of an automatic switch that would turn on the heater only when pump is on. If it got too hot, I could turn off pump but as a safety precaution, I don't want to heater on without the pump....

      3. Thanks guys I'll do it on my pool,
        Heat the water a little to be more comfortable.

      4. Do you use any chemicals to control the PH levels?

      5. Hello ladies! Just wanted to wish you well! I can't wait for cocktail pool season and I bet you can't either - especially now that most of us are spending a lot more time at home these days. You guys are awesome!!

      6. Hiw did the heater impact your electric bill?

      7. So this is amazing!! My one question I cant seem to figure out how you've covered the heater, right now by description and diagram, the live wires look exposed. Am I missing something? Help! Thanks.