How To Clean a Stainless Steel Hot Tub Pool

02 July 2024

Spaflo hot tub cleaning equipment next to a stainless steel hot tub

We are often asked how to clean a hot tub, particularly a stainless steel hot tub which might have different cleaning requirements. Regular maintenance and cleaning of your stainless steel hot tub is important if you want to enjoy it for a long time, so in this guide we are going to share cleaning and maintenance tips.

1. How often should you clean a hot tub?

You should aim to clean your hot tub weekly.

Any sized pool or hot tub will over time develop a naturally occurring ‘scum line’ along the resting level of the surface water. This comes from calcium deposits build-up due to the reaction between oxygen in the atmosphere and the water beneath the surface. By using a clean microfibre cloth moistened with pool water to clean the stainless steel that sits above and just below the water level you are helping to prevent a ‘scum line’ forming.

Alternatively it may be easier to perform this quick clean either just before or immediately after each use.

2. What equipment or products do you need to clean a hot tub?

Basic cleaning equipment:

Microfibre cloth
Pool net and pole
Spa Wand (optional)
Underwater Vacuum

At a basic and routine weekly level, Microfibre cloths are an essential and readily available item which should help keep your stainless steel looking fantastic.

Should you wish to remove any underwater and/or surface debris, a pool net and pole will further help. If you wish to concentrate on cleaning underwater, you can use either a Spa Wand which is a manual pump action vacuum, or you can further automate by purchasing an ‘underwater vacuum’. This is a pole connected to the plant room (for larger pools and spas) via a hose with a vacuum head attachment which uses the vacuum point built into many pools to rid the water of any natural debris.

In the event that your Stainless Steel requires a deeper clean you can use dedicated Stainless Steel cleaning products but only do so with advice from your pool specialist in advance.

3. Do I need a professional to clean my hot tub?

No, you can do all of the regular cleaning and maintenance yourself. For a deeper clean, you should contact your pool specialist.

4. Are the chemicals used in hot tubs safe?

All chemicals will contain irritants and feature safety warnings.

Only big commercial pools use chemicals that should never be mixed.

5. How much chlorine to add to the hot tub

Most normal pools, spas and hot tubs will typically use either chlorine or bromine as a sanitiser and will have pH - and + added to achieve the correct pH balance every week.

How much chlorine to add to your hot tub depends on the type of chlorine you are using and how much water your pool holds. Generally, it is recommended to use 1-3 chlorine tablets per 500 gallons of water per week. This will vary depending on the size of your hot tub and how much use it gets.

Chlorine is usually available as a tablet or granules. Tablets tend to come in smaller (20g) or larger (200g) sizes - we would usually recommend the smaller tablet for hot tubs as the larger tablets are better for bigger swimming pools and spas.

6. How to adjust pH levels in your pool or hot tub

The pH level of your hot tub is an important part of the cleaning and maintenance routine. pH levels measure the acidity levels of the water, where 0 is highly acidic, 7 is neutral and 14 is high-alkaline. You should be aiming to keep the hot tub at a near-neutral pH level of between 7.2 and 7.8 as this keeps the water crystal clear and allows the chlorine to do its job of sanitising properly.

When filled from a household water tap, the pH level of your pool water will be a certain level which you will need to measure. The pH level will never be the same from pool to pool as it depends on many factors, including whereabouts you live. For example, in southern areas of the UK you find more hard water which has a higher pH (more alkaline), so will need more pH- (acid) to balance it out.

Maintaining the pH balance is an ongoing process because it can be altered very easily. For example, sun cream from a swimmer's body, chlorine or anything falling in the water can shift the pH level.

We recommend measuring the pH level of your water weekly as a minimum. You can add acids and alkalis into the water depending on the pH level to balance it out.

When adding chemicals, it is always better to add a little at a time and retest until you achieve the right balance.

Once the pH and alkalinity is right water will become crystal clear again.

Pool and spa owners get to know how their pool works quite quickly by fine tuning the balance between cleaning, chemicals and shocking.

7. How and why to ‘shock’ your hot tub

Once treated with the chlorine and pH chemicals, the water should also go through a process of ‘shocking’. This is adding a higher dose of oxidising chemicals to your hot tub and it has multiple benefits;

Kills bacteria
Removes organic contaminants - heavy use can lead to lots of waterborne organic contaminants which regular chlorine dosage might struggle to cope with. Shocking the water can quickly remove these pollutants.
Reactivate sanitiser - the shocking process can reactivate the sanitiser already in the water (chlorine or bromine) and allow it to keep killing bacteria between treatments.

‘Shocks’ are classed as an ‘oxidiser’ and can be either chlorine or non-chlorine based. Any nasties (bugs, algaes etc) are broken down by the chlorine/bromine tablets ready for reoxidisation through ‘shocking’ which frees up the chemical balance.

8. Can I use my hot tub straight after cleaning?

If you add shock we recommend you leave the lid off for 30 mins at least whilst the pumps are running. This allows the gasses to escape whilst the reaction takes place.

You may choose to use a test strip before use just to make sure the levels are safe for swimming.

9. When to empty a hot tub?

You might be wondering when and how to empty your hot tub once you have filled it and used it for a while.

Hot tubs and swim spas typically feature much smaller and more compactly designed equipment such as the Cartridge Filter. A cartridge filter can be removed from its plastic housing, cleaned of biofilm and debris and then re-inserted. However, it should ideally be fully dried before being re-used so many people rotate a couple of filters.

Hot tubs and spa pools should be drained empty after super heavy use, or if left unused for a long time.

Otherwise, BISHTA and PEWTAG recommend that you check and change the water every 1-3 months depending on usage and pH levels.

Similarly a Pool with a sand filter needs to be backwashed for a few minutes. ‘Backwashing’ is when the water is sent in the opposite direction through the filter. The backwashing process utilises the filtration pump to send water through the sand filter in the opposite direction which removes any debris settled in the sand and fluses it away. The tank can then be rinsed and the water sent back the right way through the pool filters.

10. What happens if something spills into the hot tub water?

If you spill something in the water, you should test and regain the water balance as required. You don’t need to worry too much about a small amount of fruit juice or similar. Very large spills might be difficult to balance and may need draining and refilling.

If your tub is contaminated by broken glass it needs to be emptied and completely cleaned.

11. What natural or household items can I use to clean my hot tub?

For stainless steel top edges, use only a microfiber cloth. If you really need to, a specialist stainless steel cleaner can be used but you should check with your pool specialist if you have any doubts.

Avoid anything soap based and stick with the recommended water treatments outlined above.

12. Do I need to do any preparation before cleaning my hot tub?

Make sure you have the right chemicals in the correct dosage ready before you begin testing and cleaning your hot tub. If you need to adjust the pH or chlorine but do not have the correct dosage, you may end up leaving the water in an imbalanced state for too long which can cause unwanted chemical reactions.

Check the water balance with pH test strips first and work out the chemical amounts required. Add what you need to the hot tub and leave for 30 minutes and then re-test.

13. Are there any products I definitely shouldn’t use?

Do not use anything that contains soap or anything that has not been specifically recommended by your pool specialist. If in doubt leave it out.

14. Does stainless need to be polished or buffed?

Regular cleaning with a microfiber cloth should suffice. If left unused for a long time ‘tea staining’ may occur and a slightly more aggressive cleaning agent may be required. In this event always consult your specialist to treat.

15. Is it easier to clean stainless steel or acrylic & tiled hot tubs?

Tiles can be very difficult to maintain and keep clean - typically there are many grout lines and grout is a naturally gritty material which is difficult to clean. The crevices and cracks which are features of grout-based solutions create a perfect breeding ground for algaes and bugs to thrive on.

Acrylic-based products are usually vac formed and in areas where there is not as much water movement coupled with the additional jeopardy of UV means more dirt and more cleaning.

Stainless Steel by nature does not feature as many rolls or folds which means there is only one surface to maintain and as there is no risk of delamination this makes for an easy to care for product.

16. Are there any risks with cleaning stainless steel?

Microfiber cloths should always be free of grit and dirt to reduce risk of abrasion to the material.

Incorrect chemicals or products (such as soap) can damage the stainless steel in an irreparable way. Stick to the recommended products or ask your pool specialist if you aren’t sure.