Low alkalinity can cause many issues for maintaining a pool. If your alkalinity is low it could have an effect on your pH level, rendering the levels unstable no matter how hard you try to level them out. This would include a rapidly dropping pH level or a lower effect of chlorine’s ability to keep your pool clear, clean and blue. A low alkalinity level can also cause eye burning and cause excessive metal corrosion and potentially stain your pool finish. Fortunately, it is not very difficult to raise your alkalinity level in the pool and avoid these problems before they have a chance to develop.
Before You Begin
As always with handling any type of chemical, be sure to read and familiarize yourself with the emergency procedures and to take all proper safety precautions. Also, be sure that your pool is in good working order before you begin so you don't waste chemicals on a leaking pool.
Be sure to read all warning labels on the chemical containers and chemical testers and have gloves and all other recommended safety supplies with you to limit the risk of exposure.
Equipment / Tools
- Scooper or cup
- Alkalinity powder
Test the Pool
There are two main ways to test the chemical levels in a pool. The first way is to test with a testing strip. This method tests by dipping a stick or strip into the pool water for a few seconds and then matching up the colored pads to the legend on the bottle to determine the level.
The second method involves using droppers. It's a more accurate method, since you are less likely to get false readings from any contamination. For the dropper method, you will follow the instructions on your individual test kit, which would generally instruct you to fill up a small cylinder with pool water and add a predetermined number of drops. Once the drops are added you then swirl the water being careful not to spill anything (otherwise the test must be repeated) and then match the color up with the included chart. These kits are often three steps, and the third step instructs you to add drops “until the color stops getting darker." In this case, it is best to swirl the liquid after every drop or two and stop as soon as you notice the water color stops changing.
Adjust the Level
Adjusting the alkalinity level is the same as adjusting any other chemical once you've determined how low it is. You simply determine how much additional chemical is needed (a general rule of thumb is 2 pounds of chemicals for every 10,000 gallons of water) and slowly add the chemical with the scooper directly in front of the pool return to help mix it in.
Remember that you can always add more chemicals but cannot remove them once they've already been added, so it's best to be on the more cautious side.
Brush the Floor of the Pool
Once you have added all of the chemical adjustments, brush the pool floor under where you added them to help avoid any chemical staining of your liner or pool finish.
Retest the Pool's pH
After adding the alkalinity powder, wait 24 hours to retest. Adjust levels accordingly.
Can You Raise the Alkalinity in Your Pool Naturally?
If your alkalinity level in your pool is low and you don’t have any alkalinity powder to add, there is another product you can use in a pinch. Most alkalinity powder available at a pool supply store is just concentrated sodium bicarbonate — which is basically the same thing as baking soda. Baking soda generally is not as concentrated, but when added to your pool it will produce the same result.
Add whatever chemical you choose to raise the alkalinity and wait 24 hours to retest your levels, then readjust accordingly to avoid adding too much alkalinity to your water.
When to Call a Professional
If at any point during this process you do not feel comfortable or have an adverse
reaction to this or any other chemical you come in contact with, stop immediately and call a professional.