How To Lower Alkalinity In Hot Tub With Muriatic Acid. Common choices are liquid muriatic acid or dry sodium bisulfate. Start up the hot tubs pumps;
Note it is important to turn off the jets and the pump when adding the acid in order to lower alkalinity. Muriatic acid works best in still water. When the acid is introduced to the water, it increases the hydrogen concentration and lowers the ph.
To lower ph and total alkalinity, use a strong acid such as muriatic acid, sulfuric acid, or sodium bisulfate, all of which lower both ph and ta, but at different rates.
The only way to lower alkalinity in your hot tub is by using an acid. Your ta is 300ppm, you want to lower it to 60ppm, in a 350 gal tub. Muriatic acid must be handled carefully because if it gets on your skin, it’ll burn it within seconds. Test hot tub alkalinity regularly.