Testing Your Hot Tub Water


The best way to ensure your hot tub or spa’s longevity is to maintain proper water chemistry. Keeping the spa clean, the equipment in full working order, and the hot tub water balanced is a surefire to way extend its life and make for easy and constant usage. The best way to do that is by testing your hot tub water frequently and maintaining proper levels.

We’ve written several more in-depth articles about each of these elements of stable water so feel free to click on the links throughout this post if you need additional information. This particular article is meant as to be more of an overview.

Depending on usage, hot tub water can get a lot of buildup in it from soaps, perfumes, cosmetics, lotions, and other kinds of things that rub off of a bathers body when they use a hot tub. Because most people probably don’t do what’s recommended and shower before they get in, this often results in water balance getting out of whack or your system getting gunked up.

Monitor Your Usage

If you use your hot tub frequently it’s accommodating a lot of people, you’ll want to check your water balance after each usage and shock your system weekly. If you’re a light user, you probably need to be sure to at least check your water once a week and shock as needed. For a clearer idea of what regular maintenance entails, check out our post on a hot tub cleaning schedule that is easy to follow.


Hot Tub Water Testing

Water testing is pretty simple, for the most part. Here are some terms you should be familiar with when you start testing your hot tub water.

PPM: This simply stands for “parts per million,” in reference to the amount of a given chemical in the water. This is typically the term of measurement you’ll when testing your water.

Alkalinity: Alkalinity, often referred to as “total alkalinity” (or TA) needs to be balanced before you measure and assess your pH levels. TA should fall in the range of 80-120 PPM to be considered balanced. If you do this backwards and adjust your pH levels first, your alkalinity will be affected.

pH: The pH of your hot tub water is a measure of how acidic or basic it is. If you did well in high school chemistry, this should ring some bells. It’s is a very important factor in keeping water balanced because if your water becomes acidic, it will cause major problems in your water like equipment corrosion or skin irritation. If your pH reading is high (and the water becomes basic), it often turns cloudy or scale forms along the tile work. The correct balance is a pH balance of somewhere between 7.2-7.8.

pool chemistry

Calcium Hardness: Calcium hardness or overall hardness is a reference to the amount of calcium and magnesium present in your spa water. You need some degree of calcium hardness so that it doesn’t leach out of the equipment and corrode your pipes. Calcium hardness or overall hardness should read anywhere between 250-450 PPM for plaster hot tubs and 100-249 PPM for acrylic spas.

Sanitizers: Most people sanitize their spa water with either bromine or chlorine although alternative systems (like ozone and biguanide) are becoming increasingly popular. If you use one of the former sanitizers, they should be kept between 1.5-3.0 PPM (chlorine) or 3.0-5.0 PPM (bromine).

Test Kits: Liquid vs. Strips

Liquid test kits have previously been more accurate than strips but technology has begun to catch up. Modern strips are easy to store and carry and are much more capable than previous generations. Liquid test kits still have advantages and there’s really no way to go wrong when picking a method to test your water.

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