Baking soda doses for 18,000 gallons
| Alkalinity | Pounds / ounces | Metric | pH change |
|---|---|---|---|
| TA 40 → 80 | 10 lb | 4.6 kg | +0.27 |
| TA 50 → 80 | 7.6 lb | 3.4 kg | +0.19 |
| TA 60 → 80 | 5 lb | 2.3 kg | +0.12 |
| TA 70 → 80 | 2.5 lb | 1.1 kg | +0.05 |
How much baking soda for an 18,000 gallon pool
In an 18,000 gallon pool, 2.5 lb (1.1 kg) of baking soda raises total alkalinity by 10 ppm. Going from 60 to 80 ppm takes 5 lb (2.3 kg). Baking soda nudges pH up only a little, so it is the tool for alkalinity, not for pH.
Run it with your numbers
Add
5lb
of Baking soda / alkalinity up (sodium bicarbonate)
81 oz2.3 kg
Raises total alkalinity from 60 ppm to 80 ppm in 18,000 gal. pH moves to about 7.5.
- Side effects: pH +0.12.
- Retest after the water has circulated.
Check the product label. Strengths vary by brand, so enter the % printed on yours. Add one chemical at a time, into the water, and never mix chemicals.
Save this test and get reminded when it is time to retest.
Pool Calc for iPhoneComing soon to the App StoreAbout baking soda
Plain grocery-store baking soda is the same chemical as pool "alkalinity increaser", usually for less money. Broadcast it over the deep end with the pump running, or dissolve it in a bucket first.
Add no more than 40 ppm of alkalinity at a time, then retest after a few hours. If your goal is higher pH rather than higher alkalinity, use soda ash or borax instead: baking soda cannot push pH above about 8.3.
Dosing an 18,000 gallon pool
That is about the size of a 27 ft round × 54 in above-ground pool (about 17,130 gal), or a 16 × 32 ft in-ground pool averaging 5 ft deep (about 19,150 gal), or a 15 × 30 ft in-ground pool averaging 5 ft deep (about 16,830 gal). 18,000 gallons is a typical backyard pool. Measure the volume once rather than trusting the builder’s brochure: an error of 20% in gallons makes every dose 20% off. The pool volume calculator takes a minute.
Questions
How much baking soda do I put in an 18,000 gallon pool?
2.5 lb per 10 ppm of alkalinity. From 60 to 80 ppm, 5 lb.
Does baking soda raise pH?
Slightly. It mostly raises alkalinity. To raise pH, soda ash or borax works better.
Can I swim after adding baking soda?
Yes, once it has dissolved and circulated, usually within an hour.