Hot Tub Maintenance Guide to Keep Your Spa Crystal Clear All Year

The pool’s closed for the season, snow is threatening, and suddenly that steaming hot tub in the backyard looks like the best investment you ever made. But after a few weeks of regular use, the water starts looking a little hazy, a scum line appears at the waterline, and you realize you have no idea what you’re doing. Sound familiar?

Maintaining a hot tub is simpler than you think. With the right routine for water chemistry, filter care, and regular cleaning, your spa will stay crystal clear and ready to use whenever you need to melt away the stress of an Indiana winter.

Why Hot Tub Maintenance Matters

Hot tubs are small bodies of water that heat up to around 100 degrees, creating the perfect environment for bacteria, algae, and all sorts of unwanted guests if the water isn’t properly cared for. Unlike a pool that might hold 15,000 to 30,000 gallons, your hot tub only holds around 300 to 500 gallons. That small volume means every time someone gets in, the water chemistry shifts more dramatically.

Body oils, lotions, sweat, hair products, and sunscreen all contaminate the water quickly. Add in the heat, and you’ve got a recipe for cloudy water, foam buildup, and bacteria growth if you’re not staying on top of maintenance.

Proper care keeps the water safe and comfortable, protects your equipment from damage, and extends the life of your hot tub. A well-maintained spa can last 15 to 20 years. Neglect it, and you’ll be dealing with expensive repairs or replacement long before that.

Water Chemistry: The Foundation of Hot Tub Care

Everything starts with balanced water. If your chemistry is off, nothing else works right. Your sanitizer becomes less effective, your skin gets irritated, and your equipment corrodes or scales up.

The Numbers That Matter

pH should stay between 7.2 and 7.8. This measures how acidic or alkaline your water is. Too low and the water becomes corrosive, eating away at metal components and irritating skin. Too high and your sanitizer stops working effectively, scale forms on surfaces, and the water gets cloudy.

Total alkalinity should be between 80 and 120 ppm (parts per million). Alkalinity acts as a buffer for pH, keeping it stable. If alkalinity is too low, pH will bounce all over the place and become nearly impossible to manage. Too high and pH locks in place, making it hard to adjust.

Sanitizer levels depend on what you’re using. Chlorine should read between 2 and 4 ppm, while bromine typically runs between 3 and 5 ppm.

Testing Your Water

Test your water two to three times per week using test strips or a liquid test kit. If you use the hot tub heavily (daily or multiple times per day), test it before each use. Test strips are fast and easy, giving you instant readings on pH, alkalinity, and sanitizer levels.
Dip the strip in the water for a few seconds, pull it out, and compare the color squares to the chart on the bottle. Adjust your chemicals based on what the test shows.

Chlorine or Bromine?

Most hot tub owners use either chlorine or bromine as their primary sanitizer. Both kill bacteria and keep the water safe, but they work differently.

Chlorine dissolves quickly, works fast, and tends to be less expensive. It’s the same chemical used in most pools. Chlorine works best in water with a pH between 7.2 and 7.6 and breaks down faster in hot water and sunlight.

Bromine takes longer to dissolve (sometimes a few days) but stays active longer in hot water, making it a popular choice for spas. It’s also gentler on skin and produces less odor. The downside is it costs more and doesn’t work as quickly as chlorine.

Here’s something most people don’t know: if you have both a pool and a hot tub, use the same sanitizer in both. Why? Because when you go from your chlorinated pool into a bromine hot tub (or vice versa), the mix of chemicals on your skin throws the hot tub chemistry completely out of balance. The water gets cloudy, foamy, and gross much faster.

If you’re running both, stick with chlorine in the hot tub. That way you can go back and forth between pool and spa as many times as you want without causing problems. Most people want to swim first, then finish the evening relaxing in the hot tub. Using the same sanitizer makes that possible without wrecking your water.

Using Tablets and Floaters

The easiest way to maintain consistent sanitizer levels is with 1-inch chlorine or bromine tablets in a floating dispenser. Drop one or two tablets into the floater, adjust the vents to control how much chemical releases, and let it circulate in the water.

When you get in the hot tub, pull the floater out and set it aside. You don’t want it bouncing into you while you’re trying to relax. When you’re done, toss it back in.

Adjusting pH and Alkalinity

If your pH or alkalinity reads too high, use granular pH down (also called dry acid) to bring it back into range. Dry acid is safer and easier to control in a hot tub than liquid muriatic acid, which is too aggressive for small water volumes. Add small amounts, retest after a few hours, and adjust again if needed.

If pH or alkalinity is too low, use a pH increaser (sodium carbonate) or an alkalinity increaser (sodium bicarbonate) to raise the levels. Again, go slow and retest.

Shocking Your Hot Tub

Shocking (also called oxidizing) reactivates sanitizers and eliminates organic contaminants like body oils, sweat, and lotions. Even if your sanitizer levels look good, shock helps keep the water clear and fresh.

There are two types of shock. Non-chlorine shock (also called oxidizing shock) works without raising chlorine levels, making it a good option to use right after getting out of the hot tub. It oxidizes contaminants and helps break them down so the filter can catch them. Add a capful when you’re done soaking for the day.

Chlorine-based shock raises your chlorine level temporarily. It’s more aggressive and better for dealing with cloudy water, algae, or heavily contaminated water. Shock treatments should be done weekly or after heavy use.

Never add shock directly to the water while people are in the hot tub, and don’t get in right after shocking. Let the jets run for 15 to 20 minutes to circulate the shock, then wait at least 30 minutes before using the spa.

Body Oils and Scum Lines

That ring around the waterline is body oil, sunscreen, lotions, and other contaminants that float to the surface. It’s sticky, gross, and harder to clean the longer it sits.

Products like Spa Perfect (similar to Pool Perfect for pools) help break down body oils so your filter can capture them instead of letting them build up on the surface. Use about 1 ounce per 100 gallons of water once a week. For an average 400-gallon hot tub, that’s about 3 to 4 ounces.

This keeps the scum line manageable and reduces how often you need to scrub the waterline.

Alex and Cory break down hot tub maintenance in this quick walkthrough.

Cleaning Your Hot Tub

The Waterline and Shell

Even with enzymes like Spa Perfect, you’ll still need to scrub the waterline periodically. Use a soft-bristle brush or a non-abrasive sponge with a little white vinegar or a hot tub cleaner made specifically for spas. Never use household cleaners like bathroom sprays or abrasive scrubbers. They can scratch the shell, leave residue, and throw your water chemistry off.

Gently scrub around the entire waterline, rinse with clean water, and you’re done. Do this weekly if you use the hot tub frequently, or every couple of weeks for lighter use.

Cleaning the Bottom

Leaves, dirt, and debris will settle on the bottom of the hot tub, especially if it’s outdoors. You can reach down and grab larger debris by hand, but for fine particles and dirt, use a handheld spa vacuum.

Battery-powered spa vacuums (like the Pool Blaster Catfish or similar models) work great. They’re rechargeable, attach to a telescopic pole so you can reach the entire bottom without getting in, and have a clear canister so you can see when it’s full. Just turn it on, run it over the bottom of the spa, and empty the canister when you’re done.

Some manual models use a pump action, and smaller handheld versions are powered by AA batteries. Pick whatever fits your budget and needs.

Filter Maintenance

Hot tub filters should be cleaned every 2 to 4 weeks to remove built-up debris and keep water flowing properly. A clogged filter reduces circulation, strains your pump, and leads to cloudy water.

Your hot tub likely has two screw-in cartridge filters located under a gray flap on the side of the spa. Unscrew them (they have twist-lock threads) and pull them out. Rinse each filter with a garden hose, spraying between the pleats to dislodge dirt, oils, and debris.

Never use a pressure washer. The high pressure will destroy the filter pleats and ruin the cartridge. A regular garden hose with a spray nozzle works fine.

For a deeper clean, soak the filters overnight in a filter cleaning solution (available at pool and spa stores), then rinse thoroughly before reinstalling. Filters should be replaced every 6 to 12 months depending on use.

The filters are interchangeable, so it doesn’t matter which one goes in which spot. Just make sure they’re snug, finger-tight. Don’t crank them down hard or you’ll strip the threads.

Some hot tubs allow you to remove and clean the filters while the spa is running because there’s a small grate inside that prevents debris from getting into the system if a filter isn’t installed. Check your owner’s manual to see if your model allows this.

Dealing with Spa Foam

When you turn on the jets and the surface of the water erupts in thick foam, it means your water is loaded with soaps, oils, or other contaminants. Foamy water is usually caused by high concentrations of soap or body oils.

Foam reducers (sometimes called foam-free or defoamer) can temporarily knock down the foam. Add a teaspoon at a time and let it work. But foam reducers are a band-aid, not a solution. They coat your filter cartridges and eventually reduce filtration efficiency.

The real fix is to clean or replace your filters, shock the water, and make sure bathers rinse off before getting in the hot tub. If foam keeps coming back despite clean filters and balanced chemistry, it’s time to drain and refill the spa.

Draining and Refilling Your Hot Tub

Hot tubs should be drained and refilled every 3 to 4 months, depending on how often you use it. Over time, dissolved solids, minerals, and chemicals build up in the water. No amount of shocking or balancing will fix water that’s just plain old and saturated.

To drain your hot tub, turn off the power at the breaker. Locate the drain valve (usually on the front or back corner at the base of the spa, or in the equipment area behind the skirt panel). Attach a garden hose to the drain and run it to a safe drainage area.

Draining by gravity takes a while. Speed things up by using a submersible pump, which can empty a 400-gallon hot tub in about 15 minutes.

Once the spa is drained, clean the shell with a soft cloth and a hot tub cleaner or white vinegar. Wipe down the entire interior, scrub any stubborn stains, and rinse thoroughly. Check the jets while you’re at it. If they’re hard to turn or look grimy, unscrew them (turn counter-clockwise) and soak them in a cleaning solution to remove mineral deposits and buildup.

Refill the hot tub with fresh water, balance the chemistry, and you’re back in business.

Hot Tub Features and Controls

Modern hot tubs come with a control pad that manages jets, lights, temperature, and filtration. Understanding how these features work makes maintenance and operation easier.

Most control pads have two jet buttons (Jet 1 and Jet 2) that control different zones of jets throughout the spa. Turn them on for hydrotherapy, turn them off when you’re done.

Along the top edge of the hot tub, you’ll see diverter valves. Spin these to increase or decrease water flow to different areas. Want more jets on your back and fewer on your feet? Adjust the diverters. They control how water is distributed through the spa.

The light button (usually to the left of the display) turns on the LED lights in the footwell and around the diverters. Most hot tubs have color-changing LEDs that cycle through the spectrum. You can pause on a color you like or let it run through the entire rainbow.

Temperature controls let you adjust the heat up or down. Most hot tubs have a circulation pump that runs continuously, even when the jets are off. This keeps water moving through the filter and maintains temperature without having to run the larger jet pumps all the time.

Understanding these controls helps you operate the spa efficiently and troubleshoot issues when something doesn’t seem right.

Common Hot Tub Mistakes

Forgetting to test the water regularly. Water should be tested before every use or at least two to three times per week. Waiting too long between tests means chemistry drifts out of range, and you end up with bigger problems.

Using household cleaners on the shell or cover. Bathroom sprays, bleach-based cleaners, and abrasive scrubbers damage acrylic surfaces and disrupt water chemistry. Stick to products made for hot tubs.

Not cleaning or replacing filters often enough. Filters should be rinsed every 2 to 4 weeks and replaced every 6 to 12 months. A dirty filter clogs circulation, strains the pump, and leads to cloudy water.

Ignoring the cover. Hot tub covers should be cleaned regularly and inspected for damage. A damaged cover lets heat escape, increases energy costs, and allows debris into the water. Clean it with a mild cleaner every 90 days and check for cracks, warping, or water absorption.

Adding too many chemicals at once. Make small adjustments, let the water circulate for a few hours, then retest. Dumping in large amounts of chemicals throws everything out of balance and creates more problems than it solves.

Not rinsing off before getting in. Lotions, sunscreen, hair products, and body oils contaminate the water fast. A quick rinse before soaking saves you headaches later.

Winterizing and Year-Round Use

If you plan to use your hot tub through winter (which is the best time to own one), make sure the cover is in good condition and keep the water balanced. Cold air combined with hot water creates the ultimate relaxation experience.

If you’re shutting the hot tub down for an extended period (snowbirds heading south, etc.), you’ll need to winterize it properly to prevent freezing damage. That involves draining the spa completely, blowing out the lines with a wet/dry vac, and making sure no water remains in the plumbing or equipment.

For most Indiana homeowners, keeping the hot tub running all winter is the better option. Just stay on top of maintenance and enjoy it.

Hot Tub Maintenance Schedule

Save this simple maintenance schedule as your go-to checklist for keeping your spa crystal clear.

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