Hot Spring Freshwater Salt System: The Ultimate Guide

The Hot Spring Freshwater Salt System is an industry-first saltwater system for hot tubs. This system is optional on all Hot Spring Highlife , Limelight and HotSpot Spas (from 2025). The system uses salt (yes, the same salt you have on your chips!) and the unique patented titanium cartridge. This helpful guide will explain how the system works, how much it costs (start-up and ongoing), how to start-up the system, how to maintain the water and also some troubleshooting/FAQs.

Looking for information on the Freshwater Salt System WITH the IQ Smart Monitoring System? Click here for our our dedicated guide to Freshwater IQ

How Does The Hot Spring Freshwater Salt System Work?

In basic terms, the Hot Spring Freshwater Salt System uses a replaceable, patented titanium cartridge to create chlorine from salt. Salt is added to the water on start-up and the system is controlled with the hot tub control panel. The salt water flows through a cartridge containing electrodes. An electric current is applied, causing the salt (NaCl) to break down into sodium and chlorine!

What are the Benefits of the Freshwater Salt System?

Naturally-produced Chlorine. Natural chlorine produced from salt is not only a more pure chlorine, it also means less reliance on bottled chemicals, which is better for our planet.
Self-sanitising. The Freshwater Salt System self-sanitises the hot tub by itself 95% of the time. There can still be the need to add manual chlorine from time-to-time but most of the sanitisation is performed by the cartridge and salt in the water!
Fewer chemicals added. Adding fewer chemicals to the water helps to keep your levels more stable. The consistent production of chlorine helps reduce chlorine spikes and troughs, which helps general water quality.
Integrated control system. The Freshwater Salt System is fully controllable through your Hot Spring control panel. You can increase the power output, check your salt level and ensure the system is running well.
Salt Water provides a natural healing benefit to your skin.

Are there any drawbacks?

Cost. The Freshwater Salt System is more expensive than a standard chlorine water care kit. We have broken down the full costing below. In comparison, a user on bottled chlorine granules would likely spend approximatley £200 per year on chemicals (depending on usage, climate and other factors).
Requires manual dosing from time-to-time. The system will require manual dosing on start-up and during periods of heavy usage. The system cannot be 'more powerful', it can simply operate for different lengths of time from 0 to 24 hours per day. During heavy usage, the system can be supported by manual dosing of chlorine.
The system is not chlorine-free! It is a chlorine-based system and that is the core concept.
It is not set and forget. The system requires testing, ph level adjustments and you do need to manually dose from time-to-time.

How Much Does It Cost?

Start-Up Costs

Hot Spring Freshwater Starter Kit £399: https://www.happyhottubs.co.uk/hot-spring-freshwater-salt-system-starter-kit
On-The -Go Water Softener (Reccomended for Hard Water Areas) £359: https://www.happyhottubs.co.uk/on-the-go-portable-water-softener
Estimated Total Start-Up Cost £758

Ongoing Costs (Annual)

Replacement Salt Cartridges. Last 4 months each. (3 pack = £270): https://www.happyhottubs.co.uk/hot-spring-freshwater-salt-system-cartridge
Salt, Chlorine, PH Balancers and other sundries (Estimate £100 per year)
Estimated Total Ongoing Annual Cost £370 Annually

How to Start-Up The System

Step 1 - Fillling Your Spa

First, you must establish the Hardness of the water coming from your tap. You can do this with Hot Spring Freshwater 5-way or Happy Premium 4-way strips. If the Hardness is above 75ppm then you will need to use either a Hot Spring Vanishing Act or On-The-Go Water Softener to lower the Total Hardness level of your water. The On-The-Go fits inline with your hose whereas the Vanishing Act is added once the hot tub is full. Please note larger hot tubs may require 2x Vanishing Act Pillows and therefore the On-The-Go is much more cost effective as it can be re-used hundereds of times by re-charging with salt.

Once the spa is filled with water, turn the spa power on. Set the temperature to at least 35 degrees Celsius (important to get the water balanced).

Step 2 - Balance Water

Test your water using a FreshWater 5-Way Test Strip or Happy Premium 4-way Strip. Review PH and alkalinity levels to determine if your water is within the salt system’s parameters and adjust as needed (see table below for target levels).

Target Levels:

System Parameter	Target	OK Range
		Min	Max
Salt	1,750 ppm	1,500 ppm	2,000 ppm
Hardness	50 ppm	25 ppm	75 ppm
Alkalinity	80 ppm	40 ppm	120 ppm
pH	7.4	7.2	7.8
Chlorine	3 ppm	1 ppm	5 ppm

Salt - See step 3.
Hardness - If your water was not softened by a softener then you will need to add a Hot Spring Vanishing Act.
Alkalinity. Add TA Plus to raise TA. Add PH Minus to lower TA. View our guide on balancing PH and Alkalinity.
PH. Add PH Minus to decrease your PH level. Add PH Plus to increase your PH level. View our guide on balancing PH and Alkalinity.
Chlorine - Manually add chlorine granules to get Free Chlorine above 5ppm. This gives the system a good clean. We suggest manually adding chlorine for the first 3 days to help create a chlorine residual and make the salt system more efficient.

Step 3 - Add Salt (Target 1,750 ppm)

It is generally better for the water to heat up before adding salt but it can be added cold if needed. To find the correct water capacity of your spa model, check the chart in your spa owner’s manual. Make sure the spa jets are on before adding salt. To avoid over salting the water, start out by adding half the recommended amount of salt (Reference Table below), using the cup provided with your FreshWater Spa Salt. Pour the salt into the filter compartment, 1 cup at a time, with the jets running. Allow five minutes for the salt to dissolve. Use FreshWater Salt Test Strips to verify the salt level is around 1,750 ppm. Continue to add salt, one cup at a time, as needed to reach the target level. Be careful to not exceed the maximum recommended level of 2000 ppm, otherwise you will may need to partial drain to dilute the water.

Salt Dosing Table:

Spa Capacity		Salt	Output Setting
Gallons	Litres	Cups	Setting
200	760	4½	Level 5
250	950	5¾	Level 5
300	1,140	7	Level 6
350	1,330	8	Level 6
400	1,520	9¾	Level 6
450	1,710	10¾	Level 6
500	1,900	11½	Level 7
550	2,090	12½	Level 7
600	2,280	13¾	Level 7

Step 4 - Set Salt System Output Level and Monitor

NOTE: This step is typically performed on Day 2 of start-up (once the water is warm and the salt is added)

The output level of 0-10 determines how long the system runs each day. Observe your spa usage patterns and measure the chlorine level to guide your output level. Keep your output level as low as possible to maintain 1-5 ppm chlorine. By setting output level to 0 the system will stop generating chlorine. The Boost feature sets the output level to 10 so that the system runs continuously for 24 hours, overriding the current output level setting. The system returns to its previous output level once the Boost cycle is complete. Use the Boost function to gradually increase the chlorine level before or after high spa usage. The spa can still be used while in Boost mode.

Access the water care menu on your control panel and set salt system output to the recommended level indicated in the table below (Salt System Output Level). To change the Output Level, one of the three screens below on your spa's control panel will be displayed.

A good place to start is between 5 and 7 and then adjust accordingly.

Salt System Output Level
Level 0	System Off
Level 1	Vacation
Level 2-4	Low Output
Level 5-7	Normal Use (recommended)
Level 8-9	High Use
Level 10	Maximum Output
Boost	Level 10 for 24 Hours

Maintaining Your Water with the Freshwater Salt System

Ongoing maintenance includes keeping a check on balances, checking the salt system menu on the touchpad and keeping your filter clean. We have broken down each parameter and some advice on how to maintain this.

Salt - Salt level only ever increases over time (with salts taken into the spa and chemicals containing salt being added) so the general advice is to not add salt unless you top up with fresh water. You can manually check salt levels with Hot Spring Salt Test Strips.
Hardness - Hardness will stay set from fill unless you top up (with hard water). If you need to lower hardness then you can use a Hot Spring Vanishing Act.
Alkalinity. Add TA Plus to raise TA. Add PH Minus to lower TA. View our guide on balancing PH and Alkalinity.
PH. Add PH Minus to decrease your PH level. Add PH Plus to increase your PH level. View our guide on balancing PH and Alkalinity.
Chlorine - To increase chlorine level you can increase the power output, use a 'Boost' or manually dose with chlorine granules.

Other tips:

Clean your filter every 2-4 weeks with filter cleaner. See our filter cleaning guide
Add Non-Chlorine Shock once per week to help chlorine efficiency.
Setup an Auto Clean Cycle function on your control panel to keep your water well circulated and filtered.

Water Care Schedule

To try and make your hot tub water care nice and easy we have broken down what we would recommend doing in our schedule table. This schedule may not apply to all users but gives a rough guide on required maintenance.

Frequency	Action
Daily (or every 2-3 days with light usage)	Ensure chemicals are balanced. Adjust water with chemicals or amend Salt System settings if required.
Weekly	Rinse filters to remove large debris. Add Non Chlorine Shock.
Fortnightly	Clean filters with filter cleaner to de-grease them.
Every 4 Months	Flush, drain and re-fill your hot tub with fresh water. Apply protectant to cover.
Yearly	Consider an Annual Service to check components
Every 2-3 Years	Replace hot tub filters.