Why Is Refilling Your Hot Tub After Cleaning Important?

Maintaining your hot tub is essential for the longevity of the system and ensuring the water stays clean and balanced. After cleaning the hot tub — whether you’ve drained it to replace the water or just for a thorough deep clean — it’s time to refill. But did you know that the process of refilling is just as important as maintaining the water chemistry?

Refilling your hot tub properly ensures you get the best performance and water quality. A clean refill sets the stage for good water chemistry, reduces the chances of clogging your filters, and prevents wear on your hot tub's equipment.

In this guide, we’ll take you step by step through the process of refilling your hot tub after cleaning to ensure everything is set up for your next relaxing soak.

How Do I Refill My Hot Tub After Cleaning?

Refilling your hot tub isn’t difficult, but it’s important to follow these steps to ensure you fill it properly and avoid any potential issues.

Step-by-Step Process to Refill Your Hot Tub After Cleaning

1. Ensure the Hot Tub Is Cleaned and Ready

Before refilling, ensure the hot tub has been thoroughly cleaned. This includes cleaning the shell, filters, and removing any debris or dirt from the system. If you’ve just drained the water, check for any residual cleaning products or chemicals and ensure the system is completely clear.

2. Check the Water Level Sensors

Many hot tubs are equipped with water level sensors that help prevent the pump from running dry. Before you start the refill, make sure these sensors are working correctly. This will ensure that the hot tub fills evenly and that you don’t run into issues with your pump later on.

3. Attach the Hose and Begin Filling the Hot Tub

Attach a clean hose to the water source and begin filling the hot tub. Be sure to use a hose that is free from debris and chemicals, as contaminants from the hose can interfere with the water chemistry. Some homeowners opt for a pre-filter to ensure the water coming into the hot tub is as clean as possible.

Start filling slowly, and keep an eye on the water level. The water should cover the filter area, but you don’t want it to exceed the waterline indicator, which is usually just below the top edge of the hot tub.

4. Check the Filters and Equipment

While the hot tub is filling, it’s a good time to inspect the filters, pumps, and any other equipment to ensure they’re in good working order. If the filters were removed during cleaning, make sure they are properly reinstalled before continuing. Ensure that all jets are in place and the covers are properly secured.

5. Fill Until the Proper Water Level Is Reached

Once the hot tub reaches the correct water level — usually about 2-3 inches (5-8 cm) above the highest jet — stop filling. Don’t overfill, as this can put stress on the system. If you have any doubts, refer to the water level indicators or your hot tub’s manual for specific instructions.

How to Maintain Proper Water Chemistry After Refilling

Now that your hot tub is refilled, it's important to balance the water chemistry to ensure a safe and comfortable soak.

1. Test the pH Levels

Once the hot tub is full, test the pH levels of the water. The pH should ideally be between 7.4 and 7.6. Use a water testing kit to get an accurate reading, then adjust accordingly. Low pH can lead to corrosion, while high pH can cause scale buildup.

2. Add Sanitizers

The next step is to add the right amount of sanitizer. Chlorine or bromine are the most common sanitizers used in hot tubs. After filling the tub, add the recommended amount of sanitizer based on your hot tub size and manufacturer’s guidelines.

3. Adjust the Alkalinity

Test and adjust the alkalinity of the water, which helps stabilize pH levels. The recommended range for hot tubs is between 80 and 120 parts per million (ppm). This helps ensure that the pH levels stay stable and balanced.

4. Shock the Water

After refilling, it’s a good idea to shock the water. This process involves adding a higher dose of sanitizer to kill bacteria, break down organic contaminants, and restore balance to the water. Follow the manufacturer’s instructions for how much shock treatment to use.

Additional Tips for Refilling Your Hot Tub

• Monitor the Water Temperature: Once the hot tub is filled, allow the water temperature to rise to your desired level. Most hot tubs take several hours to heat up, so it’s best to start this process early if you want to soak later in the day.
• Avoid Adding Too Many Chemicals at Once: When adding chemicals, always follow the manufacturer’s instructions, and add them gradually to avoid chemical imbalances.
• Clean the Filters Regularly: To keep the water clean and your hot tub functioning properly, clean the filters regularly — ideally every 4–6 weeks. This helps prevent clogging and maintains the flow of water. For more tips, check out our Hot Tub Filters Guide.

How to Refill a Hot Tub After Cleaning

Refilling your hot tub after cleaning may seem like a simple task, but it’s essential to do it correctly to maintain water quality and ensure the longevity of your system. By following these steps and maintaining your water chemistry, you’ll keep your hot tub in optimal condition for years to come.

For more information on Hydropool’s hot tubs and swim spas, check out our Hot Tubs Catalog and Swim Spa Catalog. If you’re new to hot tubs, explore our Learning Centre for additional tips and helpful guides.

Still have questions? Reach out to your local Hydropool retailer here: Find a Retailer