Mastering Hot Tub Alkalinity

Mastering Hot Tub Alkalinity

If you are new to hot tubbing, you may have thought Alkalinity and pH were the same and not something to worry about. Other hot tubers like yourself may not be sure about the difference, so you read articles like this to learn more.

So let’s start with what Alkalinity actually is. Alkalinity is the presence of calcium, magnesium, and other compounds in your water that act as a buffer against swings in your pH level. It works to hold your pH levels in place, so it remains balanced, preventing rapid swings in your water chemistry. Think of it as your first line of defense for maintaining healthy, clear water.

When you test Alkalinity and the difference from what pH is. With Alkalinity, you are measuring your water’s capacity to prevent pH from drifting up or down. On the flip side, when testing your pH, you measure how acidic or basic your water is. So to recap, Alkalinity is made up of minerals that prevent pH from getting out of control.

Where should it be? The recommended alkalinity range for hot tub water is between 80 and 120 parts per million or ppm. You can quickly test this at home using a reliable water testing kit or test strips. I would suggest for beginners to test your water once a week. Once you get this down, skip a week and test your water twice a month if you use your hot tub regularly.

My preference when testing water is what we call a drop kit. It uses reactive drops to measure your levels. I think the colors are much easier to read, and the color won’t change over time during the test as a strip does. If you prefer one-on-one advice, I recommend taking a cup-sized water sample to your local hot tub store, and they can check it for you.

Why Alkalinity is So Important

Now You might be asking what happens if you ignore your alkalinity levels. When your alkalinity dips below 80 ppm.

This can lead to a host of issues, including:

  • Corrosion of your Equipment
  • Etching and staining of your equipment surfaces
  • Uncomfortable burning or itching of your eyes and skin
  • Your water takes on an unsightly green hue and can be confused with algae growth.
  • And, of course, Wild pH fluctuations.

Going the other way, if your alkalinity climbs above 120 ppm.

This can result in:

  • Your Equipment scaling and potentially being damaged
  • As in Low Alkalinity, discomfort from burning or itching of the eyes and skin
  • Your water turns cloudy and unappealing to soak in
  • Also, when pH becomes Elevated, it is harder to lower the alkalinity

So what causes alkalinity fluctuations in your hot tub water? They can range from natural environmental influences like rain and other debris falling into your hot tub to bodily reactions of everyday products applied to your skin and hair. Even regular chemical treatments can have a plus or minus effect on your alkalinity.

So Let’s dive in a little deeper into the causes of those highs and lows and how to fix them.

When you have high Alkalinity, the number one reason for this is using a water source that already has high alkalinity. Second is body oils and lotions introduced into the water while soaking in your hot tub. Another cause is going overboard with calcium-based chlorine that pushes your alkalinity upwards. The fourth one I learned while making this video. As your water naturally evaporates, the minerals and other alkaline compounds in the water become more concentrated, leading to higher alkalinity levels.

How do you fix a high alkalinity level? You have two options one is Muriatic Acid which is a liquid, and the other is Sodium Bisulfate, a granular powder. Both are widely used to lower alkalinity in your water with a small side of pH. Meaning any alkalinity adjustments you make, up or down, will have a slight impact on your pH.

Before using Muriatic Acid, proceed with caution. While effective, it does require careful handling due to its caustic nature. Make sure to follow the instructions on the bottle or consult your local hot tub professional for proper use, even though it requires extra care. Most hot tub stores lean towards Muriatic Acid as a solution as it is more cost-effective and more concentrated than Sodium Bisulfate, which is primarily used to lower pH.

Now, what decreases your alkalinity? Just as in low alkalinity, your water source or rain can be the issue. Also, using chemicals like chlorine or bromine in your hot tub can cause reactions that gradually lower alkalinity over time. Even certain types of microbial activity in your water, while unpleasant to think about, can consume alkaline compounds as part of their diet. In addition to all of that, acidic oils and lotions can also alter your water chemistry and decrease alkalinity levels.

To raise your alkalinity back up, you would use ordinary Baking Soda, which is Sodium Bicarbonate. Just as in lowering alkalinity, this will also have a small impact on pH levels since alkalinity and pH are so interconnected.

My advice when making any adjustments is to do them gradually. It’s better to do small doses rather than attempting a major adjustment and overshooting the mark.

By Keeping your alkalinity levels in check ensures a more enjoyable hot tub experience and adds to the longevity of your beloved hot tub and its components.

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