How to Clean a Hot Tub
Before you empty your hot tub for cleaning, run a special cleanser through the lines to remove any mold or bacteria. Once the lines are clean, turn off the power to the hot tub, then drain the tub according to the manufacturer's instructions. Wipe down the surface of the hot tub with a specially-formulated hot tub cleaner, then rinse the shell completely and wipe it down with a towel. Remove your filter and run it through your dishwasher, then clean the inside of your filter cabinet with the hot tub cleaner. Reinstall the filters and refill your hot tub, then enjoy.
Consider flushing the lines of your tub before draining. Hot tubs run at a temperature where many kinds of mold, bacteria, and other organisms can flourish and live in the inner workings. If you replace all the water without flushing the lines first, you risk contaminating the new water. You can keep your tub cleanest by regularly running special cleaner through its lines, a process called "flushing the lines," to eject and cleanse bacteria and gunk. A line flush for your hot tube should be available at your local pool supply store, but may also be available at your local hardware store. Be sure you specify that you need a line flush for a hot tub, as many different kinds of line flush exist. Depending on the line flush you purchase, the procedure for application may vary. Generally, you'll add the flush to your hot tube while it is running for a period of time indicated in the instructions of the flush treatment. Lines that have build up can result in decreased jet pressure, cloudiness in the water, or increased pressure (and strain) on your pump motor. Flushing your lines will help your tub run smoothly and efficiently. Turn off power to your hot tub. Forgetting to cut power to your tub could result in its pump kicking on when there's not enough water, which could do damage to the motor of your hot tub pump and filter mechanism. To ensure your tub is completely off, you may want to go to the fuse box and flip the breaker for the circuit that's supplying it power to the "OFF" position. Turning off the circuit breaker as well as switching your tub to off can prevent others from accidentally turning it on if you take a break when cleaning or have to leave to pick up more supplies. A damaged pump can be an expensive and unnecessary expense. Drain the water in your tub. This should be done according to the directions that came with your hot tub. Most often this involves the use of a built-in sump pump or a drain plug to remove the water from the reservoir of your tub. Many manufacturers also recommend leaving the foot-well of your tub full of water. If flushing your lines has released a cloudy discharge into the water, you may have to completely empty your hot tub of water. After doing so, you should rinse your tub to remove any remaining line particles. Then you can fill the foot-well of your tub, if necessary. Apply a hot tub cleaner to the surface of the tub. In many cases, specially formulated hot tub cleaners will easily cut through dirtiness. These special cleaners will also protect the shell of your tub from damage that can be caused by abrasive particles in other cleaners. Spray down the interior of your tub with a hose to moisten it, and then scrub with your cleaner and a rag or sponge. Acrylic hot tub shells are resistant to buildup and germ aggregation. If your tub has an acrylic shell, you may be able to clean your hot tub with a mild, general-purpose bathroom cleaner. For more thorough cleaning you can mix a batch of chlorine solution that is 50 parts per million (ppm). You can create this mixture simply by mixing ¼ teaspoon of dichlor into 5 gallons (19 L) of water. After cleaning the inner shell of your hot tub, you should thoroughly rinse it out and wipe it down with an old towel. Leaving behind cleaner can affect the chemical balance of your hot tub, which can hurt your water clarity or create an environment where mold or bacteria could grow. Remove and thoroughly clean your filter(s). These are often accessible through an access panel or cabinet located around your pump. Some filters may require you to unscrew or unfasten catches that hold the filter casing in place. You may want to take a picture of the filter assembly before you begin to take it apart so you know how it's supposed to look when fully assembled. After you have removed your filter(s) you should: Spray your filter(s) off with a jet of water. A normal, high-pressure garden hose nozzle should be sufficient to remove most residue from the filter. Do not use a brush on your filter; this can cause dirt to become deeply entrenched in it. Scrub the inside of your filter cabinet with your tub cleaner or a 50 ppm dichlor/water solution. Bacteria or organic matter, like mold, can grow in the housing of your filter. Even if it appears clean at a glance, give it a good scrub to keep it that way. Place your filter for at least an hour in an oil-cutting solution. The appropriate solution for your tub make and model will likely be in your hot tub instruction manual, but if not a representative at your local pool supply store can help you find the right one for your tub. Disinfect your filter(s) in a chlorine solution. A 50 ppm chlorine solution works well to disinfect and break up any grime that remains after your oil cutting soak. You can create this mixture simply by mixing ¼ teaspoon of dichlor into 5 gallons (19 L) of water. Run your filter(s) through your dishwasher. This is an alternative to soaking your filter(s) in an oil-cutting solution and disinfecting with a dichlor/water rinse. First you'll want to remove as much grime from it as you can by spraying the filter(s) with a high-powered stream of water from a hose. Once you have removed as much grime as possible, put your filter by itself into your dishwasher. Then: Use the normal amount of detergent and turn off the heat-dry cycle. Run your filter through the dishwasher twice for best results. In between wash cycles, you'll want to turn your filter over. This will ensure that your filter gets cleaned all over thoroughly and completely. Check your instruction manual before attempting to clean your filter in your dishwasher. Some hot tubs might not be designed to withstand the sanitizing temperatures of your dishwasher. Reinstall your filters. This may be as easy as sliding the filter(s) into a coupling and pressing the covering panel back in place, but you may need to consult the picture you took of the filter fully assembled for more complicated designs. Be sure that all necessary parts and fasteners are in place and secure. Isolate problem areas with effective cleaners. Some dirtiness in your hot tub can be most effectively cleaned by the use of specific cleaning agents. For example, white water lines can be dissolved with a 50/50 mixture of white vinegar and water. Simply apply the vinegar/water solution to the afflicted area with a sponge or rag and scrub or wipe it clean. You should also: Use baking soda for busting up gunk and and organic goo. The extra abrasion of baking soda in addition to its cleaning properties will help your rag or sponge cut through the dirtiness, but is gentle enough that it should leave your acrylic shell unaffected. Apply olive oil to sap or pitch that has gotten on your hot tub or hot tub cover. Rub the oil into the stained area until the sap/pitch begins to break up, then wipe the surface clean with a rag, mild soap, and water. Add water to the designated water line for your tub. You'll want to run the water you are adding to your tub through the filter(s) of it first. Place your hose inside the well of your filter housing so that the water flows through the filter(s) of your tub, into its lines, and finally into the reservoir of the tub. Return power to your hot tub. If you have turned the circuit breaker for your hot tub off, you'll need to set this to "ON" before reactivating your tub. Allow your hot tub to run a few minutes while you listen to the pump/filter for any odd noises. These can be indicators that you've improperly reinstalled the filter or haven't fastened the catches holding it in place properly. You'll also want to turn all the air valves of your hot tub off. This will prevent your hot tub from aerating too much when you treat your hot tub water. Treat the water with the chemicals recommended for your tub. The recommended combination for your hot tub will vary according to your model, but you can generally assume the need for a shock agent, a sanitizer, and potentially a pH balancer. Cover your now clean hot tub after adding your treatment chemicals and wait the time designated on the treatment instructions. Test your hot tub after the shock/sanitization wait time has elapsed. Make sure that the chlorine and pH levels are acceptable for your hot tub. The appropriate levels are usually indicated in your hot tub user manual/instructions. Sanitize the hot tub on a weekly basis. Depending on the size of your hot tub and the chemicals you are using to treat the water, there are many small differences in how you might do this. In most cases, you will only need to add a chlorine or bromine tablet to the hot tub every week to keep the water clean and sparkling. Never mix treatments that are not specifically indicated as compatible. Using the wrong mix of water treating chemicals can result in serious danger. Clean the hot tub filter once every month. The filter is a part of the hot tub intentionally designed to trap particles. This being the case, you should clean your filter at least once a month, though you might consider cleaning every two weeks for heavily used tubs. A clean filter will not only ensure proper hot tub function, it will also prolong the life of your filters. Clean the hot tub shell every three months. Most acrylic shells are resistant to bacteria, mold, and other kinds of buildup. However, by wiping down your hot tub regularly, you'll be preventing buildup from happening before it becomes thick and difficult to remove. Clean the hot tub cover monthly. The outside part of the hot tub cover is the most exposed to sunlight and the elements, so it's prone to collecting things like dirt and sap. Wipe down the cover at least once per month. Vinyl protectant is available for the outside of your hot tub cover and will help keep it from developing unsightly cracks. Clean the underside of the hot tub cover by taking the cover off the tub, and spraying it with a hose. Cleaners are not needed for this side of the cover. 
Consider flushing the lines of your tub before draining. Turn off power to your hot tub. Drain the water in your tub. Apply a hot tub cleaner to the surface of the tub. Remove and thoroughly clean your filter(s). Run your filter(s) through your dishwasher. Reinstall your filters. Isolate problem areas with effective cleaners. Add water to the designated water line for your tub. Return power to your hot tub. Treat the water with the chemicals recommended for your tub. Sanitize the hot tub on a weekly basis. Clean the hot tub filter once every month. Clean the hot tub shell every three months. Clean the hot tub cover monthly. 