Koi Pond Water Quality

Here are the numbers you should strive for in your pond for happy and healthy fish:

Ammonia is the most toxic and will cause death in very low concentrations (0.15 ppm or 0.15 mg/liter). A good pond with an active biologic filter should read under 0.1 mg/liter. Acceptable level = 0

Nitrite over 0.1 mg/l, according to your test results, you should do a partial water exchange. Acceptable level = 0

Nitrate if this level is over 20 mg/l you should do a partial water exchange or add the appropriate amount of AmQuell+©. Optimum is less then 60 ppm however the closer to 0 ppm is best.

PH indicates the ratio of Hydrogen ions (acidic) to Hydroxyl ions (alkaline) on a logarithmic scale from 0 (pure Acid) to 14 (pure alkaline). Pure water is 7.0, meaning that there is an equal balance of hydrogen ions and hydroxyl ions. Most tap water is around 7.4 to 7.6, which is perfect for Koi, as they do best in water at 7.2 - 8.0. Koi can actually tolerate a wide range of PH, from 6.5 all the way up to 9.0, but they cannot tolerate a rapid change, no more than 0.2 per hour. Acceptable rang for happy Koi is 7.4 - 8.4.

Temperature is often viewed by pond owners as a guide to feeding more than it is as a health issue for their Koi. Water temperature should be monitored for both daily swings and seasonal extremes. Temperature affects dissolved oxygen levels, respiration, metabolic rate, PH balance, free ammonia/ionized ammonia ratio and osmo-regulation. Koi can tolerate a broad rang of temperatures, from ponds that are iced over to water up to 90 degrees F, better than they can tolerate sudden shifts temperatures. If you have a shallow pond (less than 2 feet deep) in full summer sun with cool summer nights, the pond temperature may be changing by more than 4 degrees F. An hour causing stress to your fish. Greater splashing of the water (with a water fall) and shading may help control the temperature fluctuation. If your pond is subject to stressful temp changes, a 0.1% solution of sea salt containing Calcium, potassium, sodium and trace elements will reduce the stress as it aids the Koi’s osmo-regulation. As with PH, do not drastically alter the ponds’ temperature by, for instance, adding ice in the summer! Do it slowly. Koi can tolerate a low to high temp change better than they can a high to low change.

Water Hardness consists of two elements, permanent or general hardness and temporary or carbonate/bicarbonate hardness. Koi do better in hard water because of the relation of salt within their bodies to the dissolved salts in the pond water. In soft water, the difference in salt concentrations means the Koi have to work harder, through the process of osmo-regulation, to prevent the salts within their bodies from diffusing out through their gill membranes. Harder water allows the Koi to ease up on osmo-regulation and therefore reduces stress. As mentioned above, bicarbonate ions buffer the water, reducing the PH shifts, another cause of stress in Koi. Koi do well in carbonate hardness of 150-300 mg/liter or 9-18 degrees dH. In most Koi ponds the water is too soft due to the fact that there is no natural mud bottom that leaches minerals into the water. Marine salt and sodium bicarbonate increase hardness, and will also cause pH to go up. A permanent salt solution of 0.1% is beneficial to Koi, and works out to about eight pounds per 1,000 gallons. Check your pH if you add salt, and do not use table salt - the salt used to make salt water aquariums is the best. Salt will not evaporate out, and needs to be replaced only if water is drained from the pond.

Dissolved oxygen is usually only a warm weather concern, as it is associated with water temperature and algae. However, the larger the fish, the greater its oxygen demand - low oxygen levels will stress and kill your biggest fish. Ponds that have been safe may become unsafe as your fish grow larger. The colder the water, the greater its capacity to hold dissolved oxygen. Algae take up oxygen at night, and an algae bloom can cause suffocation in large fish and inhibit the oxidation process of nitrifying bacteria. Also, dying algae and decaying organic material take up oxygen. Testing for dissolved oxygen allows you to determine if your pond has the maximum amount for the temperature of the water. Splashing the water into small droplets with a fountain or waterfalls is best for aeration, although venturi valves on underwater jets and air compressors also do a good job of oxygenation.

Chlorine and Chloramine should be tested for if your water supply is from any source other than your own well. Chlorine will burn off by itself in a day or so, but chloramine must be broken down and removed chemically. Check with your local water agency to determine whether they add chlorine or chloramine. These chemicals damage the gills and liver, and even in low concentrations can cause stress that ultimately leads to disease. Also, frequently overlooked is the fact that they are added to the water supply to kill bacteria. The beneficial, nitrifying bacteria in your biological can be killed off by chlorine or chloramine in concentrations that do no obvious damage to your fish.

Copper should be tested for if water is supplied to the pond via copper pipes or if coins are thrown in the pond. Copper, in its most toxic free form, will leach into softer water more readily than into hard water.

The third thing you should do is a thorough pond cleaning;

Remove any debris i.e. dead leaves and settled solids from the bottom of the pond, Clean out your filters, Clean out your settling tank, Make sure your bottom drain/s have good water flow, clean out your surface skimmer basket/brushes.

Next you should do a 40% - 50% water change. Use a de-chlorinator like AmQuell +© if you are on city water. This product will Remove/detoxify all of the kinds of toxic nitrogen compounds in the water and all forms of ammonia, ammonium, nitrites & nitrates from the water, including the ammonia in chloramines.

If after a few days the water in your pond checks out to be within normal limits yet your fish are still showing signs of sickness, then we suggest you Isolate the fish, or fishes in question, from the rest of your pond into a “self” contained, (Isolated from the main pond water system), holding tank, with excellent water quality and adequate filtration. This Isolation Tank should also be “salted”.