Why Does My Hot Tub Feel Slimy, Gritty, Sticky, Or Greasy? The Solutions

Why Does My Hot Tub Feel Slimy, Gritty, Or Sticky

Does your hot tub feel slimy or gritty? This happens often, especially when there are unwanted chemicals in the spa. Don’t worry! The issue can easily be taken care of. You just need to know the possible causes.

Chalky water, sticky hot tub surfaces, and gritty feelings on the surface of your hot tub are caused by several different chemicals used in cleaning and maintaining the hot tub water. Calcium buildup could also be responsible for it.

You just got your hot tub – brand new and clean. You have been using it for weeks now. But all of a sudden, the comforting and relaxing feeling you normally get does not feel the same anymore. Now you are uncomfortable each time you try to soak in your hot tub – not what you paid for. Your spa now has slime and grits on the surface. Well, this is a small challenge you can easily handle.

What causes a gritty feeling in a hot tub?

A gritty feeling, which seems like the surface of your hot tub has sands on it or is like sandpaper is caused by an excess build-up of calcium in the hot tub water. This can be as a result of excessive calcium in the water source from which the hot tub is filled, or calcium that comes out of the solution in the hot tub at certain conditions. 

Calcium build-up in hot tub water occurs when the pH level of water in the hot tub is high, above the ideal level of 7.4-7.6. At such a high pH level, coupled with the heat from the warm water in the hot tub, minerals in the water are forced to crystallize or fall out of the solution.

Is hot tub slime dangerous?

Slime or biofilm is a group of bacteria and micro-organisms that group and stick together. As they are in constant contact with the hot tub water they create a protective layer of slime over themselves.

Slime in hot tubs is dangerous as they are capable of housing very harmful bacteria like the Legionella bacteria. This Legionella causes a mild flu illness known as Pontiac fever and a type of pneumonia known as Legionnaires’ disease.

Slime when in large number reduces the effectiveness of disinfectants meant to get rid of bacteria and other micro-organisms in the hot tub. And as such, bacteria growth will continually increase and leading to clogging of hot tub piping. It also causes cloudy hot tub water.

The regular warmth of the hot tub water provides a good environment for slime. Slime thrives in dark and warm water. Unfortunately, that is the kind of environment hot tubs provide.

Since slime is immune to water disinfectants like chlorine, proper care should be taken. Regularly drain the hot tub and clean thoroughly with appropriate cleaning agents – preferably scrub with a mild cloth.

How to get rid of hot tub slime

How do I fix a slimy hot tub? The best way to get rid of hot tub slime is to avoid them from appearing in the first instance. Knowing what causes slime is the first step in preventing slime. Hot tub slime usually comes from dirty and damaged filters, imbalanced water TA and pH levels, and dissolved chemicals on the human body, the hot tub users. Sweat, creams, lotions, deodorants, skin oil, perfumes, and other daily product we use on our skin and hair contribute gradually to slime formation. Regular scheduled cleaning and maintenance actions are an effective way of preventing hot tub slime. 

They include covering your hot tub when not in use, regular rinsing of hot tub filters, timely drain, and clean practices, and balancing your water TA and pH levels. A pH level between 7.2 and 7.4 will help to increase the effectiveness of your sanitizers.

If you already have a slime in your spa, you can get rid of it in the following way:

  • Clean and rinse the various parts of your hot tub, like the cover and filter. Rinse thoroughly with water and timely with chemical cleaner for even deeper cleaning of the filter. A clean filter will function effectively in filtering impurities from entering the hot tub.
  • Shock your hot tub water with enough chemicals to kill as many bacteria and micro-organisms as possible.
  • Drain your hot tub completely to remove the water contaminated with bacteria.
  • Finally, scrub clean your hot tub shell and piping, especially anywhere that is in constant contact with water.
Hot Tub Bacteria

How do you know if you have bacteria in your hot tub?

You are not the only one that craves what the hot tub offers. Bacteria also crave for the warmth and dark waters offered by different parts of your hot tub. Unfortunately for them, nobody likes the thought of having bacteria around, let alone having them floating around at the one place you choose to unwind and relax.

They are responsible for causing skin issues like hot tub folliculitis referred to as pseudomonas folliculitis or Jacuzzi folliculitis. As the primary causes of infections, you really would not want to have one unpleasant rash or itchy feeling before you realize you have a bacteria problem. Knowing when there is one and addressing it immediately will not just save your skin and health, but would also ensure your spa is in good condition.

One obvious sign that shows you have bacteria in your hot tub is when the water becomes smelly. Clean and clear water having an unpleasant smell says some bacteria are hiding somewhere in your hot tub. The presence of slime or biofilm from bacteria reduces the effectiveness of disinfectants and some chemicals.

This causes a chemical buildup in the hot tub water. So next time you are having an increasing chemical scent, it might not just be because of the use of excessive chemicals, consider adding bacteria to the list.

What kills bacteria in a hot tub?

Several chemicals can be used to kill bacteria lurking in the corners of your hot tub and putting you at risk during soak times. The popular ones are chlorine and bromine.

Chlorine and chlorine-based disinfectants are cheap and convenient way to kill bacteria. However, you do not want to use one that is too acidic as it will stain the walls of your hot tub, leave deposits on parts, and also a chemical smell.

There are chlorine compounds made specifically for hot tubs, like the chlorine chlor which is not too acidic and safe to use in dissolved form in hot tubs.

Bromine and bromine compounds are other effective bacteria killers. They are even more effective than chlorine compounds and do not produce much chemical odor. They are more preferable for hot tub use but are more expensive. Sodium bromide is a popular bromine compound used in hot tubs.

Vinegar In A Hot Tub

Can I put vinegar in my hot tub?

Vinegar is a natural all-purpose cleaner used for a variety of cleaning needs in households, and so it can be used in hot tubs too. Made from fermenting plant parts that contain contains acetic acids, vinegar is perfectly safe for cleaning as it contains no harmful chemicals.

It can also be used for any hot tub cleaning purpose, from eliminating bacteria, slime, down to cleaning and unclogging hot tub pipes and jets. There are different varieties of vinegar with different colors and scents depending on the source material used in the fermentation process, but for hot tub use, diluted white vinegar is recommended as it is colorless and leaves no stain during and after cleaning.

How to get rid of calcium in a hot tub

Already having flake-like chunks on your water surface and probably clogging of your hot tub plumbing? You have to start thinking about getting rid of the calcium deposit that is responsible before it makes your hot tub uncomfortable for use.

But then it should be noted that calcium plays an important role in the control of the alkalinity and acidity of water in the hot tub. Best said it controls the corrosiveness of water in the hot tub.

So the goal is not to eliminate the presence of calcium in the water, but to get rid of the hardened calcium flakes and control the calcium level to prevent more from coming out of the solution. 

Very low calcium level leads to corrosion of hot tub parts and components, while very high calcium levels give rise to flaky water in your hot tub. Calcium in a hot tub can be eliminated by the use of acid cleaners.

You can use vinegar to scrub the hot tub thoroughly, adjust the hot tub water pH and alkalinity levels with appropriate chemicals. This helps to loosen up the calcium crystals and make them start dissipating. 

Avoid using household cleaning agents that are not indicated for hot tub use as they can damage the hot tub shell surface with scratches and also cause foaming of hot tub water.

Limescale in a hot tub

Limescale is a deposit from hard water that is composed of calcium and magnesium. They are found on surfaces with constant contact with hard water. So if you have hard water in your hot tub, without proper hot tub care, limescale problems might come knocking soon.

And when they do, your hot tub will look unappealing to the eyes with a faded, dirty and unclean look as a result of the limescale deposit on the surfaces of the tub. You would not want to soak that does not look nice, would you? Also, limescale will not just make your hot tub ugly but will also target the components causing damages to it if left untreated.

As a hot tub gets used time after time, the alkaline level of the water in the tub gradually increases with each usage. This is faster when many people use the hot tub.

The alkaline level of the water increases due to dissolved chemicals like oils, cream, and lotion from the skin and hair of those entering the hot tub. At a high level of alkalinity, water becomes hard and limescale starts getting deposited from the solution.

Your water source can also be responsible for limescale build-up in your hot tub. If you find yourself living in an area where there is a high mineral deposit in the ground, minerals like limestone, the water available in such area tend to be hard water as a result of the high mineral content. When this ends up in your hot tub, over time, limescale will appear in your hot tub.

Fix Slimy Hot Tub

Hot tub anti-scale

Minerals dissolve in water when heat is applied, and then come out of the solution as the water cools. Hence your hot tub is a place where limescale will surely occur due to the temperature required for its functionality.

There are many hot tub anti-scale products in the market to choose from. They contribute well towards the overall comfort derived from using a hot tub. They dissolve and prevent scaling without affecting the chlorine or bromine levels of the water since they are neutral chemicals.

Hence they ensure your hot tub water stays clean, comfortable, and non-corrosive, a good condition for the hot tub components and piping to remain in good shape.

Aside from the use of anti-scale products to prevent limescale in hot tub water, other methods can be used to make your hot tub a bit immune to limescale and save you the stress and cost of having to repair components corroded by scales and draining and refilling the hot tub again.

First, target at reducing your calcium buildup. There is a common mineral that is responsible for scaling in hot tubs. One way of doing this is to reduce the number of dissolved minerals entering your hot tub with the water when filling. The use of a high-quality filter will go a long will in reducing not just calcium build-up but also preventing limescale.

As earlier said, high alkalinity can lead to limescale. So check the TA level of water in your hot tub and adjust to the appropriate level. This will not only reduce the precipitation rate but can eliminate it if the ideal TA level is constantly being maintained.


A chalky, gritty, sticky, greasy, sandy, or slimy feel in your hot tub can all be prevented and controlled by frequent and timely hot tub water care actions. This might seem little but would go a long way in ensuring you get the value for what you paid for.

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