The Minimum Chemical Kit for an Inflatable Hot Tub (and What You Can Skip): Questions Answered

Hot Tub Care
Tub and Pool Answers Team

When you’re putting together a chemical kit for your inflatable hot tub, it’s easy to get drawn into buying products that promise clearer or better-smelling water. But your first concern should be safety: keeping the sanitiser at an effective level. Which items are truly essential to prevent bacteria growth, and which are just cosmetic extras? This hub answers the questions that separate the safety-critical from the optional.

Is a starter kit worth buying for an inflatable hot tub?

Most starter kits you see on Amazon or from dealers are overpriced and include products you will rarely use. Instead of buying a bag of random chemicals, you are better off investing in the four specific items that actually keep the water safe and clear. You can build a much more effective kit for a similar price by choosing the right products individually. Full details in our guide to The Minimum Chemical Kit for an Inflatable Hot Tub (and What You Can Skip).

Should I use chlorine or bromine in my Lay-Z-Spa?

The choice between the two depends on how often you use the tub and whether anyone has sensitive skin. Chlorine is generally cheaper and easier to use, but bromine is more stable in warmer water and often gentler on skin. You must also check your specific manufacturer’s guidelines to ensure you are using a product they officially permit. Full details in our guide to Chlorine or Bromine in an Inflatable Hot Tub: Which Suits How You Actually Use It.

How much chlorine do I actually need for a first fill?

The amount of chlorine required depends entirely on the size of your tub and the concentration of the specific product you are using. A small inflatable model might only need a few grams, while larger models require significantly more to reach the safe sanitising level. You cannot rely on a generic “scoop” because tubs vary in capacity and products vary in strength. Full details in our guide to How Much Chlorine Does an Inflatable Hot Tub Really Need?.

What is the difference between chlorine shock and non-chlorine shock?

Chlorine shock is a strong sanitiser that kills bacteria and breaks down chloramines, while non-chlorine shock (MPS) is an oxidiser that clears water without adding chlorine. Using the wrong one can lead to skin irritation or water that remains cloudy. Full details in our guide to Non-Chlorine Shock vs Chlorine Shock: When Each One Earns Its Place.

Are test strips accurate enough for a home hot tub?

Test strips are fast and convenient, but liquid test kits offer a much higher level of precision for monitoring your water chemistry. The gap between the two is exactly where water problems hide, especially with UK hard water affecting the baseline readings. If you want to avoid guessing and wasting money on chemicals, a liquid kit is the safer investment. Full details in our guide to Test Strips vs Liquid Test Kits: Which Is Worth Trusting for a Home Hot Tub.

Can I use bicarbonate of soda instead of alkalinity increaser?

In many cases, bicarbonate of soda works perfectly well as a budget-friendly alternative to branded alkalinity increaser. You must be careful to use pure baking soda and avoid baking powder, which contains additives that can damage your tub. It is also crucial to test the water first and dose slowly to avoid overshooting the target range. Full details in our guide to Can You Use Bicarbonate of Soda Instead of Alkalinity Increaser in a Hot Tub?.

What is the correct order for adding chemicals during startup?

The most important rule is to balance the water before you add any sanitiser, as chlorine will not work effectively if the pH or alkalinity is off. You should start by adjusting total alkalinity, then pH, and finally add your sanitiser before waiting 24 hours. Full details in our guide to Hot Tub Startup Chemicals: What You Actually Need for a First Fill.

Why is my hot tub water cloudy after a week?

Cloudy water is almost always caused by incorrect chemical balance rather than the chemicals themselves. If you have added chlorine but the pH is too high or too low, the sanitiser cannot do its job properly. You need to test the water and adjust the pH and alkalinity levels to clear the issue up. Full details in our guide to The Minimum Chemical Kit for an Inflatable Hot Tub (and What You Can Skip).

Do I really need to shock my inflatable hot tub every time I use it?

No, you should only shock your hot tub when you have been away for a few days or after a heavy session with multiple people. Shocking is a treatment for problems like chloramines and bacteria, not a regular maintenance step for every single soak. Full details in our guide to Non-Chlorine Shock vs Chlorine Shock: When Each One Earns Its Place.

Can I put chlorine granules directly into the hot tub?

You should never tip chlorine granules directly into the water without pre-dissolving them first. If you add them straight in, they can settle on the floor or the sides of the tub and cause localised damage or staining. Pre-dissolving ensures the chemical spreads evenly and reacts safely with the water. Full details in our guide to How Much Chlorine Does an Inflatable Hot Tub Really Need?.

Why does my skin sting after a soak even though the pH is fine?

This is often a sign of low total alkalinity, which makes the water corrosive and strips natural oils from your skin. Even if the pH is within the 7.2 to 7.6 range, low alkalinity can still cause that stinging sensation and dryness. You need to raise the alkalinity to create a buffer that protects both your skin and the tub’s pump. Full details in our guide to Can You Use Bicarbonate of Soda Instead of Alkalinity Increaser in a Hot Tub?.

What is the minimum amount of chlorine I need to keep the water safe?

Lay-Z-Spa guidance suggests maintaining a level between 3 and 5ppm to ensure the water is safe and hygienic. This level is enough to kill bacteria and viruses brought in by bathers without causing skin irritation or a strong smell. Check the level daily using a test strip or liquid kit to keep the water safe. Full details in our guide to The Minimum Chemical Kit for an Inflatable Hot Tub (and What You Can Skip).

Detailed guides:

For the full picture, start with our The Minimum Chemical Kit for an Inflatable Hot Tub (and What You Can Skip) .

This list covers the weekly decisions about what to keep in your kit. But when it comes to less frequent maintenance, like a full pipe flush or drain-and-refill, you face a different set of questions. For those non-routine tasks, our guide on when to drain and refill vs. treat the water walks through the breakpoint.