What Chemicals Do You Need For a Hot Tub Start Up?

Once your new hot tub has been installed and filled with water, you’ll need to add a regime of chemicals to ensure the water remains clean and safe for use. Because of the warm water and the fact that it’s constantly reused, an untreated hot tub will actually promote the growth of algae, bacteria and other nasty things that you don’t want to be soaking in. Consider this list of chemical additions to a newly started hot tub to ensure the water is safe for bathing.

Total Alkalinity

Getting the proper levels for total alkalinity will buffer extreme changes in your water’s pH (see below for more information on pH.) Total alkalinity should be the first measurement you take when starting up a hot tub as it will play an important role in regulating all subsequent chemical measurements. Ideally, total alkalinity should read between 80 and 120 parts per million (ppm.) Low alkalinity can result in skin irritation, wild swings in pH levels and etching, cracking or corrosion of the hot tub surface and metal parts. High levels of total alkalinity can result in scale formation, clogged pipes and filters and difficulty in adjusting pH levels. You can add alkalinity increaser or decreaser to achieve the ideal total alkalinity levels.


pH is the measure of how acidic or basic the water is. The pH measurement scale runs from 1 to 14 with 1 being the most acidic and 14 being the most basic. The ideal pH level for hot tubs is slightly basic at around 7.2 to 7.8. A balanced pH is important for clean and safe water as well as providing an optimal environment for other hot tub chemicals to work properly. High pH levels negatively affect the performance of chlorine sanitizers, whereas low pH levels can affect the hot tub equipment and cause skin irritation. Use a pH testing kit to determine the pH level of your water and add pH increaser or decreaser until you reach the appropriate measurements.

Water Hardness

Water hardness is the measurement of the amount of calcium and magnesium in your water. The ideal range of water hardness is between 150 and 250 ppm. Water with a measurement below 150 ppm is considered soft and can cause pitting or etching of the tub surfaces and corrosion of metal parts. When the water is too hard, it can become cloudy and clog your filter and other equipment. You can add a hardness increaser to raise low levels, but if your levels get too high, you’ll have to empty your tub and refill it with fresh water.


Sanitizers come in chlorine or bromine forms, although there has been an increase in the number of mineral sanitizers that don’t use either chlorine or bromine. When choosing your system, make sure not to switch to another system without emptying the tub and refilling it first. There are many differents forms of sanitizers ranging from solutions and powders to tablets and floating dispensers. Follow the directions of whatever system you choose to keep your water clean, clear and free from contaminants.

To find out more about hot tub maintenance, download a hot tub buyer’s guide below, or visit us at our hot tub store.

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