How to Raise Total Alkalinity in Hot Tubs

Hot tubs are well known as places of relaxation and socializing, but they are less well known as places for water testing and balancing. And we suppose that is only reasonable. If most people had to choose between thinking about relaxing versus water chemistry, we would bet that relaxation would win hands down. But the fact is that you do not need to have to know a whole lot about chemistry to maintain a hot tub. Learning a few key terms and how to measure them using simple tests is all that is needed to keep your hot tub clean and safe. You might initially be intimidated by questions about pH levels or how to raise total alkalinity levels in hot tubs, but we have put together a simple guide to help educate and put you at ease. Onwards to taking care of your hot tub’s water chemistry!

What Is Total Alkalinity in Hot Tubs?

When it comes to hot tubs, total alkalinity is the measurement of the alkaline particles dissolved in the water. These particles are key to reducing fluctuations in pH levels and act by buffering or neutralizing acids. The measurement of total alkalinity is expressed in parts per million (ppm) and should be monitored and adjusted to sit between the optimal range of 80 to 120 ppm. Getting the total alkalinity level properly balanced is the first step in balancing the overall water chemistry of the hot tub. This is because it has the ability to affect other levels such as pH and sanitizer. Measuring the total alkalinity should be done a minimum of once a week using paper test strips or liquid reagent kits. The results of these water tests will let you know if your total alkalinity levels are too high, too low, or just right.

The Effects of Low Total Alkalinity

Low total alkalinity levels will also cause the pH level of the water to fall. A lower pH level indicates the water is more acidic which can lead to the corrosion of metal hot tub parts. It can also lead to etching, staining and cracking of the hot tub walls and other surfaces. Low total alkalinity can lead to a phenomenon known as pH bounce where the pH level becomes difficult to control. Chlorine sanitizers do not function properly in acidic solutions and will become less effective as the pH level drops. Acidic water can also have consequences on the body and can lead to skin and eye irritation.

How to Raise Total Alkalinity in Hot Tubs?

Raising the total alkalinity in a hot tub requires the addition of sodium bicarbonate, known in the hot tub world as total alkalinity increaser, to the water. This is the same active ingredient found in household baking soda, although in higher concentrations. The results of the water test will let you know how much total alkalinity increaser needs to be added.

The Effects of High Total Alkalinity

If your total alkalinity levels are over 120 ppm you may start to notice the water becoming cloudy. This is because particles that are normally dissolved in the water have begun to solidify. High total alkalinity is usually caused by the accumulation of body oils and other residues such as soaps and lotions in the water. It can also be caused by a naturally hard water supply. Cloudy water can eventually result in deposits building up on the hot tub surfaces and in the pipes, drains and other components. Allowing this to continue unabated can cause clogging and undue strain on the plumbing and water pump.

How to Reduce Total Alkalinity in Hot Tubs?

Total alkalinity decreasers, composed of muriatic acid or sodium bisulfate, can be added to the hot tub to reduce the total alkalinity levels. The use of a total alkalinity reducer will also likely affect the pH level, so tests should be performed to ensure the pH level remains in the ideal range.

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