Every spa owner's dream is to have fresh, clean, perfectly balanced water waiting for them every time they step into their hot tub. Unless you're lucky enough to have someone else maintaining your water, however, you'll need to know how to take care of it yourself. Getting into the habit of regularly testing and correcting your spa's water will not only keep everything clean and healthy, but will also save you money down the road by preventing the costly replacement of parts which are vital to your spa's operation, and will be damaged by improperly balanced water.

With this in mind, here are some tips on how to keep your spa's water well-balanced!

7.4 to 7.8
Add Spa Down
Add Spa Up
Total Alkalinity
80 to 120 ppm
Add Spa Down
Add Spa Up
Calcium Hardness
400 ppm or lower
Drain & refill

*If possible, it's really best to test all of your water's conditions every day.

List of terms

pH: Positive Hydrogen. Maintaining a pH level between 7.4 and 7.8 is critical, because a proper pH balance is what allows your spa's sanitizers to work properly.
  • If your spa's pH is too low, it can corrode your spa's surfaces and equipment, eat away at plaster and concrete, use too much sanitizer, and irritate your skin and eyes.
  • If your spa's pH is too high, it can make your spa's water cloudy, leave scaly deposits on surfaces and equipment, reduce the effectiveness of your sanitizer, and irritate your eyes.
  • Daily testing of your spa's pH level is accomplished with Test Strips or Liquid Test Kits...although Test Strips are generally easier to deal with.
Total Alkalinity: Refers to the minerals in your spa which act as buffering agents, helping to stabilize your spa's pH level.
  • If your spa's Total Alkalinity is too low, the pH level will drift erratically, plus surfaces and equipment may corrode.
  • If Total Alkalinity is too high, pH level will be difficult to adjust as it will remain fixed, your spa's water may be cloudy, scaling may occur, and the effectiveness of your sanitizer will be reduced.
  • It's best to test for Total Alkalinity on a weekly basis. Paper Test Strips and Liquid Test Kits are available.
Calcium Hardness: Refers to the amount of dissolved calcium in your spa's water. Ideally, this test should be performed weekly. Paper Test Strips and Liquid Test Kits are available...but most spa owners are content to periodically let their spa's service provider or local pool & spa dealer test for Calcium Hardness.
  • If Calcium Hardness is too low, it may lead to equipment corrosion, plus plaster and concrete surfaces may be eaten away.
  • If Calcium Hardness is too high, cloudy water may result, as well as scaling of surfaces, piping, and equipment.
  • If the level of Calcium Hardness in your spa is below 200 ppm, Calcium Chloride can be added to raise it...keep in mind that very seldom should any such adjustment need to be made. If the level is above 400 ppm, however, it's best to drain your spa and start again with fresh water!
Please Note: If yours is an acrylic spa, your Calcium Hardness shouldn't be over 200-250 ppm...as higher levels can leave scaly deposits on acrylic and plastic surfaces: Gunite and concrete-surfaced spas need a higher calcium concentration.

Spa Up: A product that combines chemicals to bring your spa's pH number up: What you would use if your pH is below 7.4. Chemicals such as Sodium Carbonate are used, but usually you won't find Sodium Carbonate for sale at your pool or spa dealer...just look for Spa Up!

Spa Down: What you would use if your pH number is above 7.8. Muriatic Acid or Sodium Bisulfate are used to bring the pH number down...again, just look for Spa Down.

ppm: Parts Per Million.

*PLEASE NOTE* Spa Doc in no way guarantees that these guidelines will achieve the desired results, as every spa has different needs, based on number of bathers, atmospheric conditions, whether or not you have a proper spa cover, whether or not your spa uses an Ozonator, and a variety of other factors. These are basic guidelines based on manufacturer's suggestions and our experience after over twenty years of servicing spas. Please be certain to carefully follow all instructions and suggestions listed on whatever sanitizing and cleaning products you choose to utilize, in addition to suggestions made by your spa's manufacturer.