How to: test water and dose chlorine

Why you need to test water and use chlorine

As a commercial operator, ensuring the safety of users falls under your responsibility. This includes managing a routine for cleaning, water testing, and applying chemicals to uphold the proper water balance. We will assist you in navigating through the necessary steps to fulfil this crucial role.

Understanding the chemical levels in the water

Although every bath is different, there are some general rules when it comes to bathing water chemistry which can be applied to baths of all shapes and sizes. Your water testing kit should also contain information about the optimum levels you are hoping to find through testing.

CHLORINE: Ideal chlorine level in a pool is 1-3 ppm.		Chlorine is widely recognised for its disinfecting properties. When added to water, it effectively kills bacteria, viruses, & other microorganisms that can cause diseases and infections. If the level is a bit too low, then it’s just a case of upping the dose a little. On the other hand, if you find the levels of chlorine are too high, then stop dosage and dilute by adding water until the bath returns to the correct levels.

pH BALANCE: Ideal pH range is 7.0 - 7.6, with the optimum measure at 7.4.		pH is a key test for water acidity or alkalinity. Low pH causes eye and skin irritation and corrosion to the bath. High pH causes cloudy water and lessens the effect of chlorine. pH levels can easily be adjusted by adding fresh clean water.

To maintain daily disinfection and pH levels, it is important to test the water using a test kit and add the necessary chemicals to the bath as needed. This procedure involves calculating the levels accurately.

Frequency of water testing

Prior to opening the bath for usage every morning
During usage every 1-2hrs (minimum)
Following dosage to check efficacy of dose
After closing the unit for use every evening

Carrying out water testing

For a detailed guide on how to take water samples and conduct chemical testing, please refer to our resources provided below. Log your results on these downloadable sheets

Daily water quality test procedure and Daily water quality test record sheet
Weekly water quality test procedure and Weekly water quality test record sheet
Equipment you will need
"How To" video on water testing with the SafeSwim Meter

How to action the water testing results

Monitoring free chlorine levels in your pool water		Free chlorine involves the amount of chlorine that's able to sanitise contaminants, while combined chlorine refers to chlorine that has combined directly with the contaminants. Total chlorine is basically the sum of free chlorine and combined chlorine If you are using hypochlorite to disinfect your bath, and assuming the pH level is the advised 7.2, then the aim is to keep the free chlorine levels at 1mg per litre or below, with 0.5mg per litre as an absolute minimum. It will be easier to maintain the correct levels of free chlorine in a bath which is well-maintained and which is not allowed to become overloaded with bathers. The upper safe limit for free chlorine is 3mg per litre and if this level is passed, then chlorine dosing should be reduced. If the levels still rise, then the bath should the closed and the water diluted.
Recommended combined chlorine levels		Combined chlorine refers to chlorine that has combined directly with the contaminants. The onboard UV will also reduce free chlorine levels. The levels of combined chlorine levels should be under 50% free chlorine, and never more than 1mg per litre. If you are finding unsuitable ratios of combined to free chlorine, then you may need to dilute the water.

Water pH levels		The ideal pH range is typically 7.2 to 7.4. If you find levels higher than this, then levels of free chlorine have to be increased to ensure it is working effectively.

How to dose the water with chlorine

Using chlorine in a tablet form or liquid form - the doing instructions are different and also differ between brands. It is always advisable to follow manufacturers instructions. Be aware that the number of users will directly impact the amount of chlorine required as bacteria introduced to the water reduces the chlorine levels.

Test the water to define what level of chlorine is required
Use full PPE - goggles, gloves, breathing mask, overalls.
Calculate the required amount of chlorine based on manufacturers instructions
Place the dose into the skimmer, located at the service compartment end of the bath
Wait 15 mins and re-test the water to check that the level is above 1ppm and below 3ppm

The importance of water balance

In order for chlorine dosing to be successful, water levels must be balanced which can be looked at in more detail with the Langelier Saturation Index (LSI), a special formula which brings all of the different elements together. Best practice is to calculate the result weekly, at the same time as measuring alkalinity, TDS and calcium hardness. Kits are available to adjust the water with chemicals but the easiest way to adjust this in your Brass Monkey unit is to dilute the water.

What is the Langelier Saturation Index?

The Langelier Saturation Index is an approximate measure of the degree of saturation of calcium carbonate (CaCO3) in water. It is calculated using pH (Hydrogen Ion), Alkalinity (CaCO3), Calcium concentration, Total Dissolved Solids (TDS), and temperature of a water sample.

The Langelier Index (LSI) is calculated as follows:

LSI = pH – pHs

pH – pH Value

pHs – Saturation pH

For a more detailed look at the different levels you can test to balance the water please see a more in-depth guide here.

For further guidance and training that your team will require please see the PWTAG recommendations here