Hot Tub Scale Controls

SpaChem Spa Scale Inhibitor is specifically formulated to remove minerals and dissolved metals from source water, if left untreated they are likely to form scale deposits or stain spa and hot tub surfaces, internal pipework, fittings, and equipment. Long term exposure to scaling deposits can reduce water circulation, reduce the efficiency of heaters and can be costly to rectify.


1. Add Spa Inhibitor on commissioning and on a weekly basis
2. Initial dose on commissioning, 25ml per 1000lts of water
3. Weekly Maintenance dose; 15ml per 1000lts of water
4. Add the product directly to the water with circulation running.
5. If you experience any difficulties please contact your dealer.

• Always ensure bathers are out of the water when adding chemicals.
• Never mix with any other chemicals including cleaning products, weed killers, and chlorine products, as a dangerous reaction may occur.
• Always handle products in a well-ventilated area.
• Always wash hands thoroughly after handling chemicals.
• Store in a cool, dry, well ventilated, secure place. Ensure chemicals do not become damp in storage.
• Instructions and dosages given are a guide to the most effective use.

• This container must not be used or contaminated with any other materials.

The primary fact in which scale starts to build up is due to calcium hardness in your water, this due to your water balancing going out of balance.  It really is imperative when looking after your tub that you start with keeping a keen eye on your pH levels and your Total Alkalinity levels which are the framework to managing water effectively. 

When your water pH goes out of balance you will find that scale/calcium will start forming on your hot tub surfaces, seat wells, and in your pipework and jets. 

Spa Bacterial Controls Applications and More

Maintaining a clean and hygienic environment for your customers is vital to guarantee their comfort. Comfortable customers = happy customers and are inevitably the ones who come back to you again and again. Traditionally, keeping pool and spa water clean has been a laborious task requiring numerous chemicals and extended periods of downtime. So, how beneficial would it be for your business to be able to manage biofilm build-up, TVC's, and Pseudomonas in as little as 10 minutes? Today, we explore Chlorine Dioxide T25 and why it could be the perfect solution for you.

What is Chlorine Dioxide T25

Chlorine Dioxide is a chemical compound that has commonly been used for a wide variety of antimicrobial purposes. Alongside the disinfection of drinking water and to sterilize medical equipment, it is also highly effective at maintaining pool water in spas, gyms, and swimming environments. At SpaChem, our Chlorine Dioxide T25 tablets help to speed up your maintenance process. It has been shown to effectively fight against specific pathogens such as legionella bacteria.

How does Chlorine Dioxide T25 work?

Upon contact with water, these tablets produce a concentrated solution of chlorine dioxide. When this solution reaches the internal pipework of your pool or jacuzzi, it effectively removes pathogens such as biofilms, organic sludge, and other containments.

Read more information in our helpful blog:  https://spachem.co.uk/chlorine-dioxide-t25-chlorogene

Spa Water Management

Answer: Over the next few weeks the SpaChem team will be discussing and supporting hot tub owners with troubleshooting guides with what to do when you lift off the cover and find that the water is far from crystal clear. It doesn’t matter which make, model or size of hot tub you own; the general rule of water management is the same for all.

Starting with one of the more common colors; green.

What’s causing it?

Green hot tub water is commonly caused by a simple, non-flowering aquatic plant. Ok, that’s just a nicer way of saying that its highly probable that you have algae in your water after all, algae love to grow under the cover of your hot tub in the dark yet warm water environment.

One of the simplest methods to test if it is algae causing this problem, is to touch the inside of your hot tub walls, if it feels slightly slimy to the touch, then the chances are its algae. The likelihood is that this has happened due to either insufficient sanitizer levels (Chlorine or Bromine) in your hot tub or your filter is not performing at its best.

How to solve it.

Test the pH and alkalinity of your hot tub water and try a Hot Tub Shock / Non-Chlorine Oxy Shock. After filtering out the dead algae we would recommend that you look to clean your filter to remove any loitering algae. For more information on the products available and how to conduct a shock treatment, visit https://spachem.co.uk/hot-tub-shock

If the above has not rectified the problem and 24 hours later, your water is far from crystal clear, then it’s time to drain your water, thoroughly wipe all of the internal surfaces of your hot tub (to remove any remaining algae), replace your filter and refill with freshwater, not forgetting to balance your waters Total Alkalinity, then pH which will ensure you are giving your sanitizer the best water environment to work at its best.

Other considerations.

There are other causes of green water such as the presence of minerals (copper, manganese, and iron is the main culprits) from the pipes that fill your hot tub, or even present in your household water and don’t forget the no-go rules around fake tan. The chemicals in your hot tub will react with the fake tan and result in some interesting shades of brown and green on the sides of your hot tub and in the water!

Hot Tub pH Balancing Controls and More

The potential issues of having unbalanced alkaline levels in your hot tub water are that it can have an adverse effect on your hot tub's appearance, cause knock-on problems to your pH readings and even affect your skin.

High pH readings on the other hand can cause scale build upon your hot tub components and deposits on the surface of your spa, can contribute to the appearance of cloudy, dull, or even foaming water and affect the efficiency of your water sanitizer which in turn adds risk to your friends and family using your hot tub.

Recommendations for addressing high levels of pH and alkalinity.

When it comes to balancing the pH and alkalinity of your hot tub water, they follow the same principles; if your levels are low, use a plus increaser and a Total Alkalinity Increaser, always remember the rule of thumb and balance your Total Alkalinity first, then your pH, if your levels are too high, use a pH & Alkalinity Reducer or Minus product!

If your alkalinity is too high, we would recommend that you… use a combined pH & Alkalinity Reducer as typically if your water is either high in pH or naturally high pH from the source then your Alkalinity normally follows suit.

If your pH is too high, we would recommend that you…. use a combined pH & Alkalinity Reducer as typically if your water is either high in Alkalinity or naturally high TA from the source then your pH normally follows suit.

To ensure that you get the right hot tub chemistry, remember the rule of thumb, and always balance your alkalinity before you address any issues with your pH readings.

The water Alkalinity or Total Alkalinity (TA) of your hot tub is a measurement of how your water is able to neutralize acids and as such is a key component to the balancing of your pH levels. The alkalinity levels act as a buffer to help your water resist drastic changes. If the alkalinity of your water is unbalanced, it can cause the pH readings to be either too high or too low. The alkalinity of your hot tub should be between 80 to 120ppm.

pH on the other hand is a measurement of how acidic or alkaline your water is. The ideal range for pH in your hot tub water is between 7.2 and 7.8, as this will allow the chlorine in your water to work more effectively at keeping your water clean. We would recommend that you check the pH level of your water a minimum of twice a week as sanitizers and minerals in the water can have an impact on your reading.

All your Hot Tub Bromine Questions

Are you finding as time goes on your spa smells? Looking forward to a nice relaxing soak in your hot tub but when you open up your spa cover you get this unpleasant odor? But the temptation of getting into what looks like a nice clean hot tub may have underlying issues. 

A hot tub that smells like rotten eggs is a sure sign that bacteria is hiding somewhere in your spa, spa parts, Jets, headrests, and spa cover, maintaining poor levels or low levels of bromine in your spa hot tub will result in high bacteria growth.  To ensure a consistent presence and dosing of bromine in your water it is recommended using a tablet dispenser for Bromine Tablets. 

So for some, this is a preferable sanitizer. However, as with any chemical sanitation system, bromine has its disadvantages. In small quantities dissolved into hot tub water, bromine is not too harmful, but it is naturally irritant to the human eyes and throat, so it’s best to avoid these areas and make sure you don’t swallow any hot tub water! 

Bromine on the other hand works by forcing apart the chemical bonds of the contaminants in your hot tub water and as it dissolves in the water it remains active, continuing to work even when it has combined with the unwanted particles.

Unsurprisingly (and like its cousin chlorine), bromine also produces a waste product which is known as bromamine. However, bromamine is not known to have as many side effects when present in your hot tub, but it will reduce the efficiency of your bromine sanitiser. If you are using bromine in your hot tub as your sanitiser of choice, you will want to test the chemical levels regularly and undertake an oxy-shock treatment if the levels need adjusting.

Its a very clear NO with regards to mixing the two sanitisers, when managing your hot tub water you need to use either or and not both together.  Bromine Granules and Bromine Tablets are fine to use together and similarly Chlorine Granules with Chlorine Tablets.  Please do not mix the two sanitizers.

SpaChem Bromine tablets for hot tubs are designed to be dosed via a specific floating dispenser or an erosion feeder device which are also slow dissolving and ideal for daily dosing, this allows it to produce free active bromine which kills bacteria and other potentially harmful organisms..

The joys of having a bromine tablet dispenser, feeder or floating dispenser gives you the peace of mind knowing that you’ll have a continual dose of bromine being dispensed into your tub 24/7.   Ps as long as there's tablets in the of course :-)

Its a great question and one that cant specifically be answered due to not knowing bather loads and average weekly usage.  However as a rule of thumb you can start with one tablet in a floating dispenser with the lowest setting open and build it up from there whilst doing daily testing to see where your levels are at.

Once you get to a happy medium on the ideal range on your test strips then your there, the only factor to remember is when you use your tub the Bromine levels will naturally drop so this is where your Bromine Granules can come into use to aid your Bromine Levels..

Remember always add small amounts, as its easier to build up, but a challenge to get back down if levels are to high.

In general, Bromine products are more expensive than Chlorine products. For example, here at SpaChem™, our chlorine products are around 20% cheaper than our bromine equivalents. This is normally due to the higher cost needed to purchase bromine. However, this can be offset by the fact that less bromine is required to get the same sanitizing power as chlorine. 

To give you more insight into bromine check out our blogs: Bromine the alternative to Chlorine & Chlorine vs Bromine

All your Hot Tub Chlorine Questions

As both products are chlorine based, they are essentially and when used correctly, as effective as each other at controlling the bacteria and sanitizing the water in your hot tub.

The key to achieving the perfect balance and level of control is to ensure your hot tub water maintains a chlorine level of 3-5ppm.

Chlorine tablets slowly dissolving in either a floating dispenser or feeder device ensure that you have a constant supply of chlorine entering your water. This method still needs to be monitored and the flow of the devices adjusted to maintain the perfect levels.

Chlorine granules added directly with their rapid dissolving properties support a more instant adjustment to the chemical levels in your hot tub water. However, if your hot tub is left unattended for a period of time, or you are unable to monitor and adjust the levels daily the chlorine demand of your water could be compromised.

The good news is whichever method of chlorine you use to stabilize the water in your hot tub, the costs are pretty similar.

If you opt for the SpaChem Spa Chlorine Granules, a 1kg tub will currently cost you from £16.92. If, however, you prefer to use the SpaChem Spa Chlorine 20g tablets, a 1kg tub will currently cost you from £14.83.

So luckily, on this occasion, price isn’t a huge influencer.

It goes without saying that care and attention must be taken when using all hot tub chemicals and this is the case for both chlorine tablets and chlorine granules.

Due to the way that they are manufactured, chlorine tablets are more acidic than chlorine granules. It is therefore important if you choose to use chlorine tablets that the floating dispenser is removed from your hot tub before you glide in.

The main risk with regards to chlorine tablets or chlorine granules not being used correctly is high elevated chlorine levels due to overuse and chlorine lock rendering the hot tub not useable. The second factor is correct pH & total alkalinity levels not being maintained at the right levels which will create an environment that will cause you tub to become too acidic or too alkaline, which will mean you burning through chlorine at a high rate.


Chlorine works by actively destroying any contaminants in the water of your hot tub. Whilst it breaks down the bacteria from the inside out, it dissolves in the water to form a waste product called chloramine.

By adding chlorine in your hot tub at least weekly, you will be able to keep chloramine at bay. You will know if you have a surplus of chloramine in your hot tub water as this is the chemical that has the notorious reputation for its unique smell, for causing stinging in the eyes and for drying the skin.

If the chlorine that you are adding as your hot tub sanitiser needs a helping hand, you can eliminate the number of chloramines in your water by doing a chlorine shock treatment. To help keep your water crystal-clear and ready to use, you will want to do this chlorine shock treatment regularly.  There are two types of shock which we will cover in our next blog, but calcium hypochlorite and an oxidizing shock call Non chlorine shock granules.

Its a very clear NO with regards to mixing the two sanitisers, when managing your hot tub water you need to use either or and not both together.  Bromine Granules and Bromine Tablets are fine to use together and similarly Chlorine Granules with Chlorine Tablets.  Please do not mix the two sanitizers.

Help & Support Chat

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