Chemical Guide

Looking after the water in your hot tub is key to making sure that it is healthy and running smoothly, and also means you will be able to enjoy your hot tub to the fullest. Daily testing and consistent small doses of chemicals will keep you water stable and elongate it’s lifespan.

Watch the video at the end of this post to see how you should test you water, which chemicals relate to which elements of the test strip and how to asses and address the levels in your water. If you keep a close eye on your water every day and treat it following this guide your water should comfortably last the 3 months recommended to keep a batch of water in you hot tub.

In the video, the use of the standard Chlorine based starter chemical kit available from Blue Whale Spa for £50 is explained. In the Chorine based starter chemical kit you will receive pH plus, pH minus, No Foam, Chlorine granules, and chlorine test strips. You can purchase individual bottles for when you are running low and everything you need can be found on our Accessories page.


Be sure to read all labels and instructions for any chemicals you purchase and keep well out of reach of children.

To take a reading of your hot tub water, dip a test strip into the centre of the hot tub for a couple of seconds and when you see the colours change shake dry. Then measure the results against the indicators on the back of the bottle. You are aiming for the colours in the outlined “Hot Tub OK” section. The top line is for Chlorine, or Bromine depending of your chemical choice, the middle is pH levels and the bottom is Alkalinity, which means how hard or soft your water is.

To increase your Chlorine levels, add a teaspoon of granules into the filter house, wait a couple minutes and then press a jet button to run it through the system. Dip another test strip to check and repeat until you reach the right level. If your Chlorine is too high, run your jets with the cover off to allow what is in the system to work through and evaporate out.

When your pH levels are in the red and too high, add a teaspoon of pH minus to bring it down. Run the jest to run it through the system and test strip again to check the results. If your pH is in the yellow and too low, use a teaspoon of pH plus to bring it up. Run the jets, test again and repeat until the correct level is achieved.

If you know that your region has hard water, with a high Alkalinity, one approach would be to purchase a different type of filter to mount on your hose when first filling the spa to soften the water. If you constantly use hard water in your hot tub it will cause damage to the internal workings of the tub. Use some Blue Whale Spa Anti Scale to reduce build-up of scale and any staining that may occur. If your water measures as too soft, with little Alkalinity, you can use Blue Whale Spa’s Alkalinity Increaser to achieve the right level on your dip test strip.

If your hot tub foaming, you will need to use No Foam, which reduces foam that can occur when incorrect cleaning products or excessive algaecide, hair products or make up, false tan creams or skin conditioners get into the water in your tub. Simply pour a capful of No Foam around the edges of your tub, activate the jets and watch the foam disappear. Drop the water level and top up with fresh water and avoid domestic household cleaners.

To recap: Every kind of chemical you could need for your hot tub is available on our Accessories page. Take a reading of your water by dipping a test strip and matching the colour results to the bottle label. To increase Chlorine add a teaspoon of Chlorine granules to the filter housing and run the jets, wait a couple minutes, dip a test strip again and repeat until a good match. To decrease Chlorine run the jets with the lid off to allow evaporation. A teaspoon of pH plus or minus with move your pH level in the desired direction with the same method. Use Anti Scale on hard water and Alkalinity Increaser on soft water. If your hot tub is foaming, pour a cap of No Foam around the edge of active jets and top up with fresh water.

If you have any further questions about the products in this video or the subjects explained, please feel free to get in touch with our sales team or customer services.

Blue Whale Spa | Hot Tub Testing Strips For Sale, Nottingham, UK

Test Strips

£12.00Add to cart

Blue Whale Spa | Hot Tub Chlorine Granules

Chlorine Granuels

£20.00Add to cart

Blue Whale Spa | pH Plus for Hot Tub

ph Plus

£20.00Add to cart

Blue Whale Spa | Hot Tub pH and Total Alkalinity Reducer

ph Minus

£20.00Add to cart