How to Drain and Refill a Caldera Spa: A Step-by-Step Guide for Fresh, Balanced Water

No matter how carefully you maintain your water, it eventually needs to be replaced. Every soak adds body oils, lotions, and dissolved solids that sanitizer and filters cannot fully remove, and over time the water becomes harder to balance and less pleasant to use. A scheduled drain and refill resets everything. With a Caldera spa, the job is straightforward if you follow the right sequence, and doing it correctly protects your heater, pumps, and water care system.

This guide covers how often to change your water, what to have on hand, a step-by-step drain procedure, and the refill and start-up process Caldera recommends.

How Often Should You Drain a Caldera Spa?

Caldera's owner's manual recommends changing your water every three to four months. Caldera also notes that spas using a salt system can often go about a year between water changes. Your actual schedule depends on how heavily the spa is used. More bathers and more frequent soaks add contaminants faster, so a busy household may need to change water at the shorter end of the range.

Signs it is time for a water change, even if you are not due on the calendar:

• Water stays cloudy even after shocking and cleaning filters.
• Persistent foam that returns quickly after treatment.
• Chemistry that will not hold steady, or sanitizer that seems to disappear.
• A lingering odor or skin irritation after soaking.

What You Will Need

• A garden hose long enough to reach a suitable drainage area
• A soft cloth or sponge and a spa-safe surface cleaner
• Filter cleaning solution and a bucket for soaking filters
• A pre-filter for your hose, such as the CleanScreen pre-filter Caldera recommends (optional but helpful)
• Test strips and balancing chemicals for pH, alkalinity, and calcium hardness
• Your sanitizer and start-up chemicals for your chosen water care system

Step-by-Step: Draining Your Caldera Spa

Drain valve designs vary by series and model year. The steps below follow Caldera's Utopia Series manual, so check your own manual for any differences.

1. Turn Off the Power

Turn off all GFCI breakers in the subpanel or main electrical panel before you begin. This is critical. Powering a spa without water can damage the heater, pumps, and controls, and that kind of damage may not be covered by warranty.

2. Locate and Open the Drain

Find the main drain valve at the bottom front of the spa. On Utopia models, you pull the handle out to its mid position, rotate it slightly to fully extend the drain tube, and then remove the drain cap. Caldera notes not to remove the drain cap while the handle is in the mid position before extending it.

3. Attach a Hose and Start the Flow

Attach a garden hose to the drain to keep water from flooding the foundation around the spa, and route the other end to an appropriate area. Then push the hose and drain tube halfway back toward the spa to start gravity flow. Spa water with a high sanitizer level can harm plants and grass, so choose your drainage spot accordingly and follow local rules on discharging spa water.

4. Let It Empty

Caldera spas drain almost completely through the drain valve. Some water will remain in the jet pump and heating system, and Caldera notes this only needs to be removed if you are winterizing.

5. Clean the Shell and Filters

Once empty, wipe down the shell with a soft cloth and a spa-safe cleaner. Avoid abrasive cleaners that can dull the surface. Remove the filters and clean them thoroughly. Caldera's maintenance guidance suggests spraying them clean, soaking overnight in a degreasing filter cleaner, and rinsing again with a garden hose before reinstalling. This is also a good time to wipe the waterline, clean the pillows, and check jets for debris.

6. Close the Drain

Remove the garden hose, replace the drain cap, and push the drain tube back into the spa.

Step-by-Step: Refilling and Starting Up

Before You Fill

Caldera's start-up cautions are worth following closely:

• Do not fill the spa with hot water. It can trip the heater's high-limit thermostat.
• Do not fill with cold water below 50 degrees F, which can also cause a high-limit trip.
• Do not connect power to an empty spa.
• If you use a biguanide sanitizer, do not add chlorine.
• After a long period or a first fill, check that the unions on either side of the pumps and heater are hand-tight.

1. Fill Through the Filter Compartment

Remove the filter compartment cover, skimmer basket, weir, and filter. Fill through the filter compartment, ideally using a pre-filter on your hose to reduce metals and contaminants in tap water. Filling this way helps push air out of the plumbing. Caldera recommends a water level about 1 inch above the highest jet in the shell. Reinstall the filter, skimmer basket, and weir once the spa is full.

2. Restore Power in the Right Order

Turn on power to the subpanel from the main house panel first, then reset the GFCI breaker in the subpanel, and finally close and secure the subpanel door.

3. Purge Air From the System

Turn the jet pumps on high. Caldera notes priming is complete when the jets run strong and without surging. Keep the diverters in the middle position during this step. If a pump runs but water does not flow from its jets, the pump is not primed. Caldera's fix is to turn off power at the breaker, loosen the union on top of the pump to let air escape, hand-tighten the union, restore power, and check that the union does not leak.

4. Set the Temperature and Balance the Water

Set the temperature between 100 and 104 degrees F, secure the cover, and let the water stabilize. Caldera notes this can take about 24 hours. Test and balance total alkalinity, calcium hardness, and pH before adding sanitizer, and follow the start-up steps for your water care system, whether that is FROG, a FreshWater salt system, or conventional sanitizer.

Planning Your Water Change Schedule

The easiest way to stay on top of water changes is to tie them to the calendar. Many Caldera owners pick the start of each season, which lines up neatly with a three-to-four-month interval and makes it easy to remember. Others pair water changes with filter deep cleans so both jobs happen in the same afternoon. Whatever system you choose, write down the date of each refill along with your starting water chemistry. Over time, that record shows you how quickly your water ages under your household's typical use, and it helps you spot problems, like a sudden jump in calcium hardness from a change in your tap water, before they cause scale or cloudy water.

Timing matters too. Pick a mild day if you can. Draining in freezing weather risks ice in the plumbing, and refilling in extreme heat can make it harder to hold temperature and chemistry steady during start-up. Plan for the spa to be out of use for about a day while it heats and stabilizes.

Common Mistakes to Avoid

• Draining with the power on. This is one of the most common causes of heater and pump problems after a water change.
• Skipping the filter cleaning. Putting dirty filters into fresh water undoes much of the benefit of the refill.
• Using household cleaners on the shell. Soap residue causes foam in new water.
• Adding sanitizer before balancing. Balanced water lets your sanitizer work efficiently from the start.
• Soaking too soon. Wait until the water is heated, balanced, and sanitized.

Frequently Asked Questions

How often should I drain my Caldera spa?

Caldera recommends every three to four months for most water care systems, and about once a year for spas using a salt system. Heavy use may call for more frequent changes.

Why won't my jets work after refilling?

The pump likely has an air lock. Turn off power at the breaker, loosen the union on top of the pump to release trapped air, hand-tighten it, and restore power.

Can I fill my Caldera spa with hot water to save time?

No. Caldera specifically warns against filling with hot water, since it can trip the high-limit thermostat and stop the spa from working. Use water that is not colder than 50 degrees F.

How long does it take a Caldera spa to heat after refilling?

Caldera suggests allowing about 24 hours for the water temperature to stabilize with the cover in place, though actual time depends on starting water temperature and conditions.

Can I use softened water in my Caldera spa?

Caldera's manual notes softened water can be used as long as calcium hardness stays within the recommended range for your water care system.

A proper drain and refill every few months is one of the simplest ways to keep your Caldera spa water clean and easy to manage. Turn off the power first, clean the shell and filters while the spa is empty, fill through the filter compartment, purge the air, and balance before sanitizing. Your fresh water will be ready to enjoy, and your equipment will thank you.