Water pH

It is extremely important to check the pH level in your pond frequently.  An acceptable pH ranges between 6 and 8.5.  The major concern of pH is the relationship of ammonia and nitrite toxicity. With 7 being neutral, every integer being an exponential increase in toxicities.

Any pH level below 7 is considered ‘acidic’, while any pH level above 7 is considered ‘basic’.

A pH over 8.5 can lead to fish disease, and eventually death.  A higher pH level is generally caused by runoff from mortar, bricks, plant pots, or other runoff.  A pH of 9 or more can damage a Koi fish’s kidneys and can lead to death.

Adding salt to the water can help by detoxifying nitrites, killing parasites, and controlling algae.  Adding too much salt can cause harm though. It is best to keep the salt level at around 0.1%.  The mixture should be around 1 tablespoon of salt for every 10 gallons of water.  It is very important to know how much water is in your pond, so that you don’t over or under treat the water with any additives.

Most pH kits range between 5 and 10, with color-coded charts to match your pH.  If you have trouble reading/ distinguishing colors, you can buy digital pH readers, but these often need calibration, and can take more time to operate than the test strips.

Chlorine

Chlorine is harmful to fish and will kill the bacteria in the pond.  It can also burn and kill aquatic plants in a pond.  If you have high levels of chlorine, it is best to remove your fish for several days.  Chlorine will dissipate in this time frame.  If you are using City water, it is best to check and see if chlorine is used.  If you want to remove chlorine from water, you can use Sodium Thiosulfate.  City water commonly contains ammonia as well.  Ammonia will harm and kill Koi fish, so be sure to test your water if you are using tap water.

When building your test kit, You want to test for these elements:

Most Important:

pH test
Ammonia
Nitrite
Temperature

 

Good to Have:

Salt
Nitrate
Dissolved Oxygen
Alkalinity

Treatment

Although pH and chemicals are important, the largest threats to life in your pond are changes.  A well-working pond will generally have an equilibrium with a pH of one half unit above or below the pH of the water used to refill the pond.  A sudden change in pH can put a fish into shock (or the equivalent of human shock).