Disclaimer: This is a long article. If you wish to succeed at making your hot tub, you need to read the entire article with full concentration. No skimming through allowed here!!
Hot tubs and spas are great. Nonetheless, they are unduly expensive. May be, their price defines their value. But, if you are anything like me, you won't be able to let yourself spend such a large sum of money. Not that it is not worth, it's just that I am a DIY kind of person. So let's start off with ways to set up your own hot tub.
There are many ways in which you can go about it. In this article, I have decided to discuss, probably, the fastest way of going about it.
Get yourself a stock tank. The size has to be as per your convenience. This can also serve as a makeshift kiddy pool. All you need to do is adjust the thermostat when you need to use it as a kiddy pool.
Place the stock tank in a sand bed. Level and smoothen the sand so that it acts as a solid base for the tank.
Next, you can start building a deck and an enclosure. It is not to support the tank, but for the effect of a big hot tub. The sand and the tub are enough to hold the weight of the water and the balance.
Now, it is time to start installing some equipment. The equipment you will require are a pump, a heater, jets, a filter, a skimmer and a control system.
You need to make holes in the tank for the skimmer, jets and the suction fittings. You will need to run all the electrical fittings through a GFCI (this could get a little pricey, but the overall cost will be lower than that of a ready-made hot tub).
First you start off with installing a skimmer. For such a hot tub, I suggest you go for a good skimmer that can be used in big above-ground pools. The mechanism is more appropriate. The skimmer is quite a big box and requires cutting a big hole in the side of the stock tank. You could try putting it higher up in the tank but I strongly suggest that you avoid cutting the rim. It could affect the structure and strength of the tank.
Next step is to decide the placement for the suction fittings and the jets. Once you have decided the places (as per convenience) drill the holes. Be careful at this part. No mistakes allowed here.
The next step is installing the jets. The purpose of the jets is to add the bubble factor to the hot tub. So you can install a good number of jets, depending on the size of the tub. Most of the jets should be plumbed to the high-speed pump and so that it can only be in use when someone is using the tub. The other jets should be plumbed to a lower powered pump, to return water that flows through the filter and the heater. This pump can be run by a timer as well as manual control so that the tub will be filtered and heated on a regular cycle even when it isn't in use.
Next step is the toughest - plumbing. There need to be wires that connect pairs of jets. This needs to be done while you install the jets in the tub. My suggestion, call in the reinforcements. A plumber will be able to do the job right.
Now we get to the suction fittings. You can purchase suction fittings. You would require 2 of 100 gpm each. The two suction fittings and the skimmer are all put in a T position together into a line. This setting will protect you from the threat of getting trapped in the suction unit or any other such disaster.
The suction line leads to another T fitting and lines to each of the pumps. Output from such a pump will go through the filter and the heater. It will be wired through a timer (as well as a manual switch) so the filter/heater run at regular intervals.
The power pump is plumbed into the filter and then into the heater and ozone injector. Although it isn't a real clean/compact design, you could try hard to reduce the resistance on the pumps.
To fit the thermostat, you will require a thermowell. It is available at stores. Nonetheless, if you are proficient enough, you could try making it from plumbing parts. The sensor (thermocouple) for the thermostat fits into the opening that is at the right of this fitting.
Downstream of the thermowell, would be the heater and the ozone injector. You could build the ozone injector from regular PVC fittings and a little lathe work. It is designed to use the Bernoulli effect to create a suction. It also draws air through the ozone generator. It would have been easier to just inject the ozone into the air intake, but it is just a matter of choice.
You could keep a valve in the output line so that you can clean the strainer basket. The line out of the pump goes to a T fitting and then each branch feeds a line that goes to the jets. This helps in reducing the resistance.
You can then do the plumbing for the air lines (for some of the jets). This is the valve on the air intake. This is strictly a passive air system. The venturi's on some of the jets will pull air in as the water flows through the system. You could try an electric air blower, but, make sure your reinforcements (plumbing expertise) is close at hand.
After the plumbing you can start installing the decking. You can use regular or treated lumber, on the basis of the area you are making the hot tub in. If you have dry climate you could go for untreated lumber, else you could choose treated lumber.
As for setting the lumber for the deck, the most conducive way would be to set it at a 45 degree angle to allow optimum and maximum support to the deck.
Now is the wiring aspect. My suggestion is get hold of an electrician. I can not help you out with electrical plans as it can be highly hazardous if tried out. So kindly get an electrician to help you out!
These are basic directions for making a hot tub for yourself. There are many more embellishments that you could put to use. But those are as per your convenience. So this is where I sign off, the writing has rendered me tired. I am going for a dip in my hot tub, I suggest you start working on yours!