Maintaining balanced hot tub water is vital to protecting you and your hot tub. A hot tub is easier to maintain when the water chemistry is regularly tested and adjusted when necessary. When a hot tub is unbalanced, it can become unsightly, uncomfortable or even hazardous to your health; over time, it can cause damage to your hot tub. In this article, we’ll go over how to test your water and each component you should check during your tests.
Tip: Download the AquaChek app to help guide decisions when testing and balancing your water. The app helps by telling you “what” and “how much” you need to put in based on the results from AquaChek test strips.
Note: The AquaChek app has some chemicals labeled differently.
- Cynuric acic = stabilizer
- Dry acid = pH Down
- Sodium Bicarbone = Alka Up
- Generic DiChlor 63% = chlorine granules
How to test your water
Before adding any chemicals, it’s essential to test your water first. The easiest and most common way to do this is using chlorine test strips or bromine test strips, depending on your sanitizer of choice.
- Turn your pump(s) on to circulate the water.
- Submerge a single test strip 6” into the hot tub water for one second before removing.
- After removing and without shaking off any excess water, wait 15 seconds before comparing the test strip colours to the colour chart on the back of the test strip bottle.
Tip: It’s helpful to either write down or take a picture of your results, as the test strip readings will continue to change.
- Adjust the chemicals in the order listed below. If you’re using the AquaChek app, input the readings you took from the test into the app for more accurate measurements of what to add.
Order of water balance
- Ensure stabilizer is in okay range (when using chlorine)
- Adjust alkalinity
- Adjust pH
- Adjust sanitizer (chlorine or bromine)
The directions for adjusting each chemical below are per 1000L, so it’s a good idea to find out your hot tub's water capacity. If you’re using the AquaChek app, it will request this as well.
If the stabilizer is too high, chlorine becomes less effective. If stabilizer levels are too low, sunlight will remove chlorine.
Stabilizer can’t be removed from the water, but it can be diluted by draining water to make room for fresh water). If stabilizer is over 100, customers should consider a drain and fill (or removing some water and adding fresh water).
Ideal range: between 80 and 140 ppm
Alkalinity acts as a pH buffer and prevents rapid changes to pH. If alkalinity is too high or too low, you'll have difficulty keeping your pH balanced. For this reason, it’s important to adjust your water’s alkalinity first.
Alkalinity reading is above 140 ppm
If your alkalinity reading is above 140 ppm, you’ll want to decrease your alkalinity (watch video) using a pH decreaser (“alkalinity down” is the same as pH down - I know this may seem a bit confusing at first).
- Add ½ a capful of pH Down (15 grams) to your hot tub per 1000L to reduce by 10 ppm; retest in 30-60 minutes.
- If you’re using the AquaChek app, pH Down is called ‘Dry Acid’.
Alkalinity reading is below 80 ppm
If your alkalinity reading is below 80 ppm, you’ll want to increase your alkalinity (watch video).
- Add ½ a capful of Alka Up (15 grams) to your hot tub per 1000L to increase by 10 ppm; retest in 30-60 minutes.
- If you’re using the AquaChek app, Alka Up is called ‘Sodium Bicarbonate’.
Ideal range:between 7.2 and 7.8
pH is a measure of how acidic or basic your hot tub water is. Water is considered acidic when your pH levels are too low and basic when pH levels are too high. When pH levels are too high, sanitizer becomes less effective; when pH is too high or too low, hot tub parts can become degraded, and water can cause irritation or become cloudy.
Before adjusting your pH, ensure that your alkalinity has been corrected and retested (otherwise, you may end up wasting chemicals).
Note: Although the ideal range for pH is 7.2-7.8, we recommend staying closer to 7.2, as keeping pH at 7.8 will result in much higher chlorine use.
pH reading is above 7.8
If your pH reading exceeds 7.8, you’ll want to decrease your pH (watch video).
- If your pH reading is between 7.8 and 8.0, add a capful of pH Down (30 grams) to your hot tub per 1000L and retest in 30-60 minutes.
- If your pH reading is above 8.0, add 2 capfuls of pH Down (60 grams) to your hot tub per 1000L and retest in 8+ hours.
- If you’re using the AquaChek app, pH Down is called ‘Dry Acid’.
pH reading is below 7.2
If your pH reading is below 7.2, you’ll want to increase your pH (watch video).
- If your pH reading is between 7.0 and 7.2, add ⅓ a capful of pH Up (10 grams) to your hot tub per 1000L and retest in 30-60 minutes.
- If your pH reading is between 6.6 and 7.0, add ½ a capful of pH Up (15 grams) to your hot tub per 1000L and retest in 30-60 minutes.
- If your pH reading is below 6.6, add a capful of pH Up (30 grams) to your hot tub and retest in 30-60 minutes.
Sanitizer (chlorine or bromine)
Ideal range: free chlorine/bromine between 3 and 5 ppm
Sanitizer keeps your hot tub free of bacteria and algae, but you’ll need to ensure your alkalinity and pH are within ideal ranges, so you don’t use more sanitizer than you need. Your sanitizer will be less effective if your pH is too high or too low.
There are only two safe sanitizers: chlorine and bromine (despite what you may read online). There are no safe-to-use alternatives, though there are products like enzymes that may help you use less sanitizer.
Free chlorine/bromine is below 3 ppm
- Add 1 teaspoon per 1000L to your hot tub and retest in 20 minutes.
Free chlorine/bromine is above 5 ppm
If your free chlorine or bromine is above 5 ppm, you can help the levels drop by leaving the cover off your hot tub (the sanitizer and water will evaporate). If your sanitizer levels are really high, add water to your hot tub to dilute it.
Ideal range: between 150 and 250 ppm
When water hardness is too high or too low, it can cause calcium scaling, foamy or cloudy water, and damage to hot tub components.
Calcium hardness is below 250 ppm
If your calcium hardness is below 250 ppm, you’ll want to increase your calcium levels (watch video).
- Add 15 grams of a calcium increaser for every 1000L of water in your hot tub; this should increase water hardness by approximately 7 ppm).
- Allow water to circulate for 30-60 minutes before retesting.
Calcium hardness is above 450 ppm
There are no chemicals that can lower water hardness. The only method to decrease water hardness is to dilute the water (empty some water and refill it with fresh water). While not recommended, if you must have high calcium hardness in your hot tub, using a stain and scale controller can help reduce problems.
Now you’re ready to enjoy your hot tub! Recheck it at least once a week to ensure your water remains balanced.