New Why Does Pond Ph Fluctuate

The pond ph varies on the time of the day you conduct the test. Ph readings done in the morning are lower compared to the tests done in the afternoon. The KH or carbon hardness of the pond water is a determining factor on how much pH will fluctuate within 24 hours. Remember that the ph levels of your pond are not stable the whole day, so dont fret as you see the readings went up or down.

What influences the pH swings in pond?

Pond ph swings are the produced from the natural gas exchange of plants. During the day, plants and other free floating algae release as much oxygen and get carbon dioxide CO2. The drop off in CO2 raises the pH in your pond, which is triggered by photosynthesis. At night, the pH decreases because the plants and oxygen consume oxygen and release CO2. Theres no wonder why low pH is detected every morning. The bacteria, blanket weeds, and sludge at the bottom of the pond may also influence the oxygen and CO2 levels in your koi pond.

How to prevent toxic pH crash in the pond?
The ph levels in koi ponds will eventually plummet without enough carbonates or carbonate hardness; thus, the efficient koi pond keeping means stabilizing the KH at a safe level of 140 and above.

A decrease in pH can be stressful and toxic to fish. The pH is measured from 1 to 14. pH level of 7 is neutral, below 7 is considered acidic, and above 7 is alkaline. A good pH reading is 7.5 in most koi and fish ponds.


The kois and either type of bacteria use the available carbonates in your pond every day. When all these carbonates are consumed, the pond pH will decrease eventually and become acidic.


you can increase the pH quickly after a ph crash, without harming the kois; however, if you attempt or force to reduce the pH instantly, then you are making your fish succumb from unstable water pH. Keep in mind that a very high ammonia reading is deadly to fish, because ammonia is more toxic than with high pH. When dealing with ammonia problem and high pH, you may change the water to drop off the high ammonia, or use ammonia remover. Pond pH buffer can also be used to balance water pH when they have gone at levels suffocating to fish.


You might want to increase the KH of your koi fish to keep it high enough overnight. If thats the case or if its just the water turns terribly lower than 7, you may add buffer to increase the carbonates. Sufficient levels of carbonates will keep the kois healthy, and much more when added with good bacteria.