Hot Tub Supply Spa Depot
Hot Tub pH & Total Alkalinity
Correcting Problems
 SpaCyclopedia Index

Pre Filter

Spa test strips This section is for those who have unusual pH and/or Total Alkalinity (TA) relationships, and have had trouble getting these indicators into balance. If you have not read the ABCs of Water Chemistry and Hot Tub Prep & Maintenance, and are new to spa water chemistry, read those pages first for a basic understanding.

99% of spa owners will have no difficulty getting their water into proper balance. But like hot tub users themselves, there's great diversity in water types from region to region, even within communities. Municipal water supplies differ from well water. This sometimes leads to difficulty in getting pH and Total Alkalinity (TA) into balance.

We have good products available to us to correct most spa water chemistry problems. Remember that since we cannot always get the chemistry perfect, it's better to have pH & TA readings which re on the high side (resulting in perhaps a bit of scale), than readings which are too low, causing equipment corrosion damage. Do the best you can, but don't lose any sleep if you can't get your readings perfect.


Problem Remedy
pH is low, but TA is normal Add Easy pH, the only product available which will raise pH, but not also raise the TA.
pH is low, but TA is high Add pH Decrease to lower TA. Then add Easy pH to raise pH.
pH and TA are both very low Add pH Increase to raise both pH and TA. Make final adjustments with Alkalinity Increaser, if necessary.
pH and TA are both high Add pH Decrease to lower high TA or pH.
pH or TA are stubbornly high Add Acid Magic to lower very high TA or pH.
pH is normal, but TA is high Add pH Decrease to lower TA. If pH also drops below normal range, then add Easy pH to bring it back up into range.
pH is normal, but TA is low Add Alkalinity Increaser to raise TA. Normal pH will not be affected.
pH is high, but TA is normal Add pH Decrease to lower pH. If TA drops below normal range, add Alkalinity Increaser to bring it back up.
pH is high, but TA is low Add pH Decrease to lower pH. Then add Alkalinity Increaser to bring TA back into range. It will not raise pH above normal range.
pH fluctuates wildly This is usually caused by low TA. Bring TA up into line with Alkalinity Increaser as needed, and make final adjustments to pH if necessary per this guide table. You can help lock pH into range with Control the pH* after adjustment.
*do not use with Cleanwater Blue system
pH drops after adding non-chlorine shock Prevent this by adding about 3/4 teaspoon Alkalinity Increaser per tablespoon of non-chlorine shock used is about right.
Bad source water or well water makes balancing difficult Reduce contaminants by using a hose-end water filling filter PreFresh Spa Fill Filter


  • IMPORTANT: After adding chemicals, allow your water to equilibrate before retesting, especially if you have been having problems with balance. This means letting the water circulate for a few hours, or retesting the next day for accurate readings.
  • Total Alkalinity should be kept between 80-120 ppm (30-90 ppm if using Cleanwater Blue system).
  • pH range is ideal between 7.2 and 7.6. Too low is acidic and will cause corrosion. Too high can result in scale formation.
  • Remove a sample of the spa water into a clean plastic cup and test it after it has cooled a few minutes, for best results.
  • Never mix different chemicals together prior to addition to the spa water. Add them one at a time. Pre-dissolving granules in a plastic bucket of water is best.
  • Make sure your water hardness is not too low. Adjust it prior to making final pH and TA adjustments. A good range for calcium hardness is 150-300 ppm. (Hardness adjustment is not normally needed or recommended if using Cleanwater Blue system).
  • Check Total Alkalinity (TA) first, then adjust for proper pH range. Proper TA will buffer pH, that is, it will help to prevent pH fluctuations.
  • Use fresh, high quality test strips.
  • Excessively high bromine or chlorine levels can result in false pH and TA readings.
  • Change your spa water at least every 3 to 4 months, depending on bather load.


Technical Information

Alkalinity Increaser is sodium bicarbonate (also called sodium hydrogen carbonate).It raises Total Alkalinity, and pH which is too low. Since it has a pH of only 8.3, it will generally have a lesser effect on pH. Diluted in water, Alkalinity Increaser will not raise pH above its normal range. Proper TA will buffer pH, and help prevent pH fluctuations.

pH Increase is sodium carbonate (also called soda ash). It raises both TA and pH, since it has a pH of 13.

Easy pH is a proprietary invention and formula which raises only pH. Easy pH has 2.5 times the pH-raising power of pH Increase.

spa customers write  Consumer Reviews
 Easy pH
"This stuff really solved my weird pH problem that I've had for years.  Amazed how well it worked without throwing my alkalinity off the scale."

Daniel Pederson
Port Orchard, WA

Spa Depot, The, Spas & Hot Tubs - Dealers, Olympia, WA

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