If you are reading this you are probably experiencing the dreaded pH drop most of us fish keeper see sooner or later. My pH has been steadily declining this summer and my water hardness is almost zero. Most koi sites will recommend a pH around 7.5 which is where the fish are happy and the nitrifying bacteria will also thrive. While there are several products on the market to raise and lower pH, one of the most effective and least expensive is baking soda. Baking soda, sodium bicarbonate, can move a ponds pH to 8.4 and help keep it there. Or it can be used in an emergency to raise pH back above 7.0 incase of emergency or lower it to 8.4 if replacement water source pH is suddenly high.
Dosage
If you are merely trying to raise your pond pH back above 7.0, use a fresh box of baking soda at 1/4 cup/1000 gallons, once every 24 hours. I personally have exceed this at 2/3rds cup/1000 gallons and my ph jumped from 7.0 to 7.8 in just a few minutes, but it is probably a little stressful for the fish. Monitor daily for the next few days.
Several manufacturers make buffers you can add to your pond to keep the pH at 7.5, or even 7.0 if you prefer. My first trial of these products was a failure. pH continued to drop. So if you use one of these, continue to check your pH regularly. Also let me know which brand worked for you.
You should test your ammonia before pushing pH higher. Ammonia becomes more toxic as pH increases. You can use an ammonia remover if needed before treatment, or just go slower increasing the pH over several days by using less baking soda. There are some who claim baking soda has an unwanted effect on koi skin quality. Using a chemical to increase pH also does not address the issues that caused the pH to drop in the first place. Baking soda is a temporary fix. Be sure to check your water hardness which will help stabilize your pH. Clean your filters too if you do not do it routinely.
