PH can be raised in three ways: borax, soda ash, and aeration. Borax is usually the best choice. Borax raises the PH and also raises the TA level just a little. If your TA level is low soda ash will raise both the PH and TA levels. If your TA level is high, aeration is best as it will not raise the TA level at all. However, aeration is rather slow compared to the other two.
Borax is available as 20 Mule TeamŪ Borax Natural Laundry Booster. It is sold in the laundry detergent section of most larger grocery stores and some big box stores. Borax is best added by pre-dissolving it in a bucket of water and then pouring that slowly in front of a return.
Soda ash is available as ARM & HAMMERŪ Super Washing Soda Detergent Booster. Do not confuse this with ARM & HAMMERŪ laundry detergent!
It is sold in the laundry detergent section of most larger grocery stores and some big box stores. It is also sold by pool stores under various names, including PH Increaser, PH Up, Balance Pak 200, etc. Soda ash is best added by pre-dissolving it in a bucket of water and then pouring that slowly in front of a return.
Aeration can be provided by a SWG, spa jets, waterfall, fountain, return pointed up so it breaks the surface, air compressor, kids splashing, rain, etc. It can take some time for aeration to raise the PH. The higher your TA level, the faster aeration will work.
TA - Total Alkalinity
TA is raised by adding baking soda. For directions on lowering TA see How to Lower Total Alkalinity.
Baking soda is common household baking soda from the baking aisle of any grocery store. If you can find them, larger containers are less expensive per pound and easier to handle. Some larger grocery stores sell baking soda in 4 lb boxes and some big box stores have it in 12 lb bags. Baking soda can be added by spreading it across the surface of the deep end of the pool.