Category Archives: Koi Pond Care

The importance of Pond Water “Oxygen Levels”

The importance of  Pond Water “Oxygen Levels” 

Pond Keepers argue ferociously about pond Oxygen levels. Some say oxygen levels are “always safe” in ponds with waterfalls and fountains, while others don’t regard fountains or waterfalls as effective aerators.

Either way, oxygen levels are very important. If the oxygen level is chronically low (for example, 5.0 ppm), the fish will grow much more slowly, they’ll get sick easier, and they may even die.

If the oxygen levels are much too low on the short term (for example 3.0-4.0 ppm), the fish will gasp or pipe at the water’s surface and they will die.

Large fish die first when oxygen levels are too low because large fish demand more oxygen to live. When the first fish dies, its body begins to break down and the decay process increases the oxygen demand of the pond even more, causing a rapid avalanche of fish losses.

Always bear in mind that warmer water (78+) carries MUCH LESS oxygen than cold water (68*). Oxygen problems are VERY common in summertime while the water is warm.

To make it worse, submerged plants and algae consume oxygen at night or in the dark. Submerged plants produce oxygen in light, or in the daytime. Plus, in warmer water the metabolism of your fish and all the bacteria (good & bad) is at its peak using much more oxygen.

Pond depth influences oxygen levels as much as temperature does. Oxygen-penetration down to five feet of water is difficult. If your pond is more than four feet deep, you will need to put a pump on the pond bottom in summer, to push the deep water to the surface for oxygenation.

Waterfalls and fountains will not aerate “deep” water unless the water is physically drawn from the bottom for these features. Oxygen levels at five to six feet may still sag, despite this.

Oxygen levels are testable, with commercial kits, or have someone test the oxygen levels for you. Assess a warmer, deeper pond much more scrupulously for oxygen problems. 

Excerpts in this article were taken from Pond Crisis an Aqua Meds website. 

Protect the health of your fish from an outside “Maintenance Service”

When you just don’t have the time or health to maintain your koi pond, you need outside help.

There are many very reliable pond maintenance services available to help with your pond maintenance.

Note: I highly recommend using a service company that your friends or neighbors use who are very happy with their service.

Many Service companies are very good at disinfecting their pond cleaning equipment between each pond customer. However, you as a pond keeper can never be 100% sure.

What was the health condition of the pond and fish your Maintenance Service, serviced before they serviced your pond? Were the fish sick with bacterial infections, did they have parasites? You cannot answer these  questions.

Here’s a simple way to protect your fish from bacterial infections and parasites brought in on the equipment of your Maintenance Service. Buy your own pond cleaning equipment. Have the service use only your equipment right down to the pails and hoses.

City Water Department cases big problems for pond keepers!

City water department
causes big problems for pond keepers!

I received a phone call from an Aqua Meds Dealer, telling me his customers were having a real problem with high ammonia.

No matter what they tried they could not bring their ammonia down to the safe level of zero.

After talking with the Dealer, he decided to test his “tap water”. Testing showed the carbonate hardness of his “tap water” was “Zero”.

After asking his pond customers what their KH tests showed, they all had KH readings of between 0 & 18.

When the Dealer made a phone call to his City Water Department, he was told they installed a new processing plant. The new process removes all the carbonates from the tap water.

That was the answer to the pond keepers ammonia problem. The “Good Bacteria” GB in the pond filters need the carbonates to flourish.

Without the carbonates the GB were not strong enough to remove the ammonia from their pond water.

Within 24 hours after the pond keepers added carbonates “Buff-it-Up” their ammonia reading was zero.

Your fish and all your good and bad bacteria in your koi pond use up carbonates 24/7. Plus, the carbonates will enhance the color of your fish.

Always try to hold a KH reading of at least 100 in your pond.


Chloramines in Drinking Water

Chloramines in Drinking Water

*Chloramines are disinfectants used to treat drinking water. Chloramines are most commonly formed when ammonia is added to chlorine to treat drinking water. The typical purpose of chloramines is to provide longer-lasting water treatment as the water moves through pipes to consumers.

This type of disinfection is known as secondary disinfection. Chloramines have been used by water utilities for almost 90 years, and their use is closely regulated. Water that contains chloramines and meets EPA regulatory standards is safe to use for drinking, cooking, bathing and other household uses.

Many utilities use chlorine as their secondary disinfectant; however, in recent years, some of them changed their secondary disinfectant to chloramines to meet disinfection byproduct regulations.

Q. How many people use drinking water that has been treated with chloramine?
**A. Approximately one-third of all public water systems in the United States use chloramine for residual disinfection

*Information from EPA
**Information from PADEP

Pond Water Changes

Pond Water Change

Water changes are simply the removal of some old pond water, and the replacement of that old pond water with new water. It sounds so simple but there are problems, nationwide.

First, tap water can be chlorinated.

Second, a lot of pond keepers don’t do water changes, at all.

Thirdly, failure to do pond water changes allows the accumulation of background pollution such as phosphates and proteins which inhibit koi fish health and growth.

Finally, water changes need to replenish trace elements and minerals in your pond water which your koi fish need.

Chlorinated and chloraminated water is usually supplied to pond keepers “at the tap” from municipal water supplies. The water company adds these two chemicals to disinfect the water.

Each day, municipal source-water is tested for eggs, spores, ova and cysts of various pathogens. If any are found, it may be that the municipal water authority will double or triple the chlorine or chloramine concentration.

Spritzing the water into the pond slowly will dissipate a lot of chlorine, but will it dissipate all of it? Dechlorinate. By de-chlorinating your tap water, you can be 100% sure the chlorine is gone and will not harm your koi fish.

Many municipal water departments use chloramine for treating your drinking water. Chloramine is a combination of chlorine and ammonia. When your municipal water supply uses Chloramine, you want to use a water conditioner which removes both chlorine and ammonia.

Note: Recently FDA has changed it’s regulations in order to improve municipal water quality.

Many utilities that have used chlorine as their disinfectant in recent years, have changed their disinfectant to chloramines to meet new disinfection byproduct regulations. You never know when your water department will make that change, if they haven’t already?

Many of the water conditioners on the market ONLY remove the chlorine from your tap water leaving the harmful ammonia in your pond water.

When purchasing a water conditioner, make sure the directions state, “removes chlorine and ammonia“. Many water conditioners state “removes chlorine and destroys chloramines”. Sure it destroys chloromines because it removes the chlorine from the chloramines however, it leaves all the deadly ammonia behind.

Some say that the amount of ammonia left behind in your pond water will not harm you koi fish. Why leave any ammonia behind in your pond water? No matter the amount, the ammonia left behind just adds to a bigger work load on you pond filter to remove. Your pond filter has enough work to do just removing the toxic ammonia produced by your koi fish.

Our Aqua Meds DeChlor & More removes both the chlorine and the ammonia from your tap water. Plus, it’s very economical.

In speaking to pond keepers from across the country, I found that about forty percent of the hobby is not doing ANY water changes at all. This accounts for recurring illness among their fish, slow growth, and poor color. This is the most common cause of seven year old Koi that are only seven inches long.

A koi in good pond water with plenty of water changes should grow at least 3-4 inches per year. I encourage you to follow a water change regimen as outlined in the chart below.

“Topping Off” your pond is not a water change. You should know this about water: The solids in pond water do NOT evaporate, nor do many of the chemicals in the water. This means that the nitrates, phosphates, a good bit of the carbon dioxide, all the salt, minerals, etc. never leave the pond and accumulate over time.

As the pond water level goes down by evaporation, you may notice that your fish perk up as you add water back.

There is a transient increase in water quality after the addition of “new” water but it’s rapidly offset by the dissolution of the existing background pollution. So, “topping off” actually concentrates solids and organic chemicals in the water over time. Real water changes are a must.

Ideal Pond Water Change Regimens

Every week 10 percent water change

OR: Every two weeks 20 percent water change

OR: Every three weeks 30 percent water change

Note: Smaller water changes more often are much healthier for your koi fish than larger pond water changes not as often.

No matter which of the above regimens you choose from above, I highly recommend that two to three times per year you should perform a 60-70% pond water change to really refresh your pond water. You will notice a real boost to your koi fish’s health and growth.

Major water change: Simply drain the pond down 60-70% and add dechlorinator. Then refill your pond. Don’t do this in the PEAK of the summer as you might chill your fish. But surely in the early summer and late summer you’ll see how happy your fish are for this major water change.

Note: with a large water change of 50% or more it’s very important to use a dechlorinator which removes chlorine and AMMONIA.

If you are performing the recommended water changes, you should have robust, hungry and healthy fish. Koi fish may still become ill, of course, however, it is much less common if your adding lots of fresh water to your koi pond on a regular schedule. Fact is, if you wouldn’t swim in the pond, your fish shouldn’t be.

Chloramines in Drinking Water

Pond Water Quality

Testing your pond water

In general, everything you should know about your pond water is available in some sort of simple pond test kit. Most kits are very easy to run. You can buy these test kits at your local shop or online. Run them at least weekly during the first part of pond opening but monthly or more during the season.

If fish ever get sick or start acting funny, you should know that SEVENTY PERCENT of fish health problems, INCLUDING vulnerability to disease-causing organisms – are related to WATER QUALITY.
Important: DO NOT make the mistake of not testing for pH and ammonia at the first sign of trouble.

  • Ammonia
    One of the most important pond water test, is testing for deadly Ammonia.
  • Nitrite
    Nitrite binds fish Red Blood Cells causing gasping and brown blood disease.
  • Nitrate
    Nitrates are a natural by-product of the bacterial “reduction” or removal of Ammonia and Nitrite in the natural pond’s ecosystem.
  • Koi Pond pH
    The pH can change overnight…In particular, the pH is prone to fall, and “crashes” are quick, and fatal.
  • Carbon Dioxide
    CO2 can exist in water independently of dissolved oxygen. If the level gets too high, even with normal dissolved oxygen levels, illness will result.
  • Dissolved Oxygen
    Oxygen is obviously essential to fish health, but how much or how little?
  • Hydrogen Sulfide
    The smell is one of rotting eggs. Losses may be great and they will continue after theH2S is long gone.

Please remember: SEVENTY PERCENT of your fish health problems are related to your pond WATER QUALITY.


Nitrates are a natural by-product of the bacterial “reduction” or removal of Ammonia and Nitrite in the natural pond’s ecosystem. Nitrates are an under-estimated fish killer.

When fish are sick, and the history contains some information to suggest the pond has been set up for a while, you can bet Nitrate levels are part of the problem.

This is especially true for Goldfish and “flipover” disease. Once dismissed as a “non” threat to Koi and Goldfish, exceptional informatioin exists to suggest this is not true. Scientists initially evaluating Nitrates as a non-toxin did not test their subjects long enough.

Nitrate accumulations cause dilation of the veins in the fins and other health problems. Never let your nitrate levels exceed 100 ppm or illness and vulnerability to disease will be the result!

Q. How do I lower my nitrates in my koi pond?
A. The best way to lower high nitrate levels without using toxic chemicals is by doing water changes.

Does my pond have too much water current?

Too much Water Current / Circulation

The Circulation of water in your koi fish pond is very important. However, too much circulation (strong current) can stress and weaken your koi pond fish.

Too much water circulation in your koi pond causes your fish to constantly be swimming. It would be like placing you on a treadmill 24/7, you would become very weak in a short time.

One good indicator of too much circulation in your koi fish pond is, your koi fish will stay in one section of your pond in order to stay out of the strong current. Only leaving their “spot” to eat.


“Should I power wash my koi pond and filter every year?”

This is a very common question I receive every spring.

A clean, clear pond full of healthy, happy koi fish should not be power washed every year!

“Mother Nature” works very hard and long to create the fragile “biological balance” of your koi pond. It does not take much to destroy this natural balance. However, it could take many months for your koi pond to recover to a healthy natural balance after a thorough cleaning. In the meantime your koi fish are being stressed.

My suggestion for spring koi pond cleaning is to remove the sludge, leaves, and twigs on the bottom of your pond. Don’t touch the green algae on your rocks and the sides of your pond. Remove all sludge from your pond filter.

Never wash your pond filter or filter pads with your tap water if you have “City Water” which contains chlorine, it will kill your “good bacteria” in your pond filter.

Weekly pond water changes are priceless to health of your koi fish and pond. Just “topping off” your koi pond water due to evaporation is not considered a water change.

It’s very unnatural for koi fish ponds to have sparkling clean rocks and sides free of healthy green algae.

If you want your pond to be sparkling clean and algae free, I suggest you have a fish-less pond.
Then you can add all the toxic algaecides you want. Plus, you can have it power washed as often as you want.

Question: Are there times when a good power wash clean out is necessary for a koi pond?

Answer: Yes, when sludge and debris become so deep it’s impossible to remove it all with the pond full of fish and water.

Some koi ponds become “sick” because of poor maintenance, lack of weekly pond water changes and they have to be power washed and cleaned.


Pond AERATION is priceless to health of your fish and your pond!!

Pond Aeration

Yes, your waterfalls add oxygen to your pond water, however, a proper sized aerator creates even more.

The importance of life supporting oxygen in your pond water
All your fish and the good and bad bacteria in your pond consume oxygen 24 hours a day. Any plants and algae in your pond produce oxygen during the day however, plants consume oxygen at night.

A fish’s gills are basically the same as our lungs are to us, they absorb oxygen. The gills give your fish the ability to absorb very low levels of oxygen from your pond water. Your pond water must contain plenty of fresh oxygen for your fish to thrive.

Pond Aeration is vital to strong, healthy, fast growing pond fish and high quality pond water.

Here are just some of the benefits of adding Aeration to your pond

• Increases the oxygen your fish and pond water need to stay healthy

• Removes toxic gases that build up in the bottom of your pond

• Helps reduce pond algae, “algae hates oxygen”

• Enables your “good bacteria” in your pond filter to multiply and thrive

• Increases “low oxygen levels” in your pond that retard growth, increase sickness and can even cause death

• Will greatly improve the performance of any “beneficial bacteria” you add to your pond water

• Stops overnight “fish kills” caused by the oxygen demand of plants and algae at night. Plants and algae produce oxygen during the day and use it up at night, called “Photosynthesis”.

• Will keep a hole open in the ice of your winter pond, plus, will remove “toxic gas build up” in your pond water all winter, reducing fish deaths in the spring.

• Increases low levels of oxygen in your koi pond during the hot summer months which cause many fish deaths each year, because warmer water contains less oxygen plus the metabolism of your fish and bacteria in your pond are at their peak demanding much more oxygen.

Here’s a sign your pond might have low oxygen:

Immediately before daylight check your koi fish to see if they are gulping for air at the surface of the water. You might scare them and they will dive deeper, only to quickly return to the surface.

If you have plants or algae in your pond, your koi fish will return to deeper water as the oxygen builds up during the day through photosynthesis.

If you’re looking to improve the health of your koi pond fish and the quality of your pond water, a pond aerator should be at the top of your list.

Catastrophic Oxygen Depletion and How to Avoid It.

Here’s how to improve the quality of your koi pond water.