Category Archives: The Water Itself

Getting Ponds and Koi Ready for Wintertime

Getting Ponds and Koi Ready for Wintertime

By Bonnie Hale Guest Author


If you must move fish inside for the winter, do this gradually. Move a few Koi inside to an aquarium or stock tank that has been set up in advance using pond water. Make sure that their winter home is large enough to accommodate them without over crowding them. Figure 1″ of fish length for every square foot of water surface. If you have a lot of extra filtration or lots of surface coverage with plants, you can bump that to 2 or 3 ” of fish for each square foot of water surface. Bring in as many plants as practical so that you have good water surface coverage. A tank, pond or aquarium that has a nice amount on surface plants will make for happier Koi. Rarely, if ever does a fish “jump” if you have good plant coverage. When they get scared they will hide under the plants. If there are no plants and the fish gets scared, he will jump out. I have never had a fish “jump out” in ponds or tanks that have good water surface coverage of plants!! But over the years I have lost my share of jumpers to tanks that do not have plants. I now keep netting over my non-plant tanks. Place lights above tank to support plants. Use a timer on the lights so that they have 10-12 hours of light a day.
If practical, move your pump and filter too so that Koi will be in almost identical situation as they were in outside. Do not move all fish inside in a new tank all at one time or they may all die. Plan to do this task early enough in the fall so that you can add a few fish every week. Monitor ammonia, pH, nitrite, and nitrate very carefully and take corrective measures if these measurements go out of balance. Feed very sparingly daily so that you do not get an ammonia spike. After a few weeks, increase feedings. My one stock tank where my favorite Koi spend the winter, get fed 3 or 4 times a day and they grow like weeds all winter long in 70 degree water.
In order for the fish to remain outside for the winter, your pond has to be a minimum of 18″ deep. If less than that, see article above about moving Koi inside.
Leave the pump run all winter or use a de-icer. Move the pump close to the surface of the water by placing it on cinder blocks or upside down clay pots. You want to have the water just bubbling just under the surface of the water. This will keep an open spot so threw which gases can escape. Once the weather gets real cold, disconnect the filter, clean it and store it. Give your filter and pump a thorough cleaning before the frosty weather hits. Store your pump in a bucket of water somewhere where it will not freeze during the winter. This will protect your seals in the pump from drying out during winter storage.
Remove frogs and tadpoles and snails. Snails and tadpoles have a hard time in the winter. Bring snails and tadpoles inside for the winter. Release the frogs (they WILL find your pond in the spring) Check ponds frequently throughout the fall and early winter for frogs and remove them. They will probably not survive in your pond for the winter because they need to burrow into the dirt for the winter. Any experienced pond person will tell you that if you leave frogs in small ponds, you will be scooping their bodies out of your pond next spring. The decay from these dead creatures will wreck havoc with your Koi. Let alone the smell!
If you live in a zone that gets cold but little or no ice during the winter, leave your filter run all winter long. It will be easier to get started in the spring. Clean it thoroughly before it gets too cold. Bacteria will not die if chilled. They will remain dormant and ready to start growing again in the spring when temperatures begin to warm up the pond.

Getting Ponds and Koi Ready for Wintertime
Getting Ponds and Koi Ready for Wintertime

Cover pond with netting or skim pond with skimmer net daily. We now have a skimmer that can be “teed” off of your pond pump. It makes removing leaves a breeze. You simply remove the leaf bag and empty out the leaves! Decaying leaves produce poisonous gases. Leaves are double trouble-solid pollution and chemical pollution. Leaves are much easier to remove in fall as they are dropping then from the bottom of the pond next spring.
Water quality at this time of the year is usually very good. The water should be crystal clear. If it is not, do small water changes every couple of days, so that it is crystal clear. Do not raise or lower the temperature more than 2 degrees at a time, as this will stress the Koi. Add water slowly and watch your thermometer. Once algae has died off the water is usually crystal clear. It is very important to keep it that way by keeping leaves; frost damaged foliage from the plants, and any other debris out of the pond. You want the bottom of the pond as clean as possible. A lot of harmful bacteria live in the fouled water. These specific pathogens are Pseudomonas and Aeromonas. They depend on foul water to attack Koi. They will not be a problem in the winter, but come spring, you had better watch out. Entire populations of fish have been wiped out in March, April & May from Aeromonas and Pseudomonas.
Because cold water holds a lot more oxygen than warm water, this is a very satisfactory time of the year for your fish because of their lower metabolism rate.
Some folks prefer to use a de-icer in their pond rather than leave their pump run all winter. The ones I sell are very energy efficient. The thermostat clicks on when the water temperature reaches 32 degrees and clicks off when it reaches 38 degrees. The deicer will keep an open spot in the ice to allow toxic gases to escape and oxygen to enter. If the pond should completely ice over do not try to open a hole by force. Use a hot tea kettle and place directly on the ice to melt a hole in the ice. My pond froze completely for 2 weeks and the Koi were just fine. Short exposures to total ice coverage did not hurt the fish at all!
Add 0.3% salt to your pond. Figure the total amount of salt that you need for your pond and add 1/3 of the TOTAL amount over a 3-day period. This equates to 3 lbs. per hundred gallons of water. Salt kills 7 of the 10 parasites that attack fish. Yes, the parasites can live in cold water! They will begin attacking the Koi in the spring as the pond starts to thaw and warm up. We had great success curing chilodenella (a parasite) a year ago in early spring using 0.3% salt. It also works great on ICH. The salt will be removed in the spring by water changes when the temperature warms up and you are ready to start adding plants.
Fortunately, bringing the Koi through the winter is fairly easy. I have had a lot of customers tell me that their fish survived the winter with flying colors then died in the spring. One word: BACTERIAL INFECTION. The salt will help tremendously. Salt will help build up extra layers of slime coat to protect the fish and it will kill parasites as previously mention.
The salt to use – Water softener salt. This is what we used. Good old Morton in the yellow bag! And it is cheap. You can use any kind of salt as long as it does not contain iodine or YPS (an
Anti caking agent) Non iodized table salt will work but it is more expensive. Don’t waste your money on expensive sea salt or aquarium salt. I give you my word that what we used is Morton water softener salt and it worked well.

*2019 Note on Salt: Iodine in salt doesn’t hurt the fish. Someone (Doc Johnson) just had to do some calculations on the actual ppb of iodine in the water versus toxicity to biological processes and organisms, prove there’s no iodophore reaction and then test it. Which I did and nothing happens.

Koi do not have stomachs. Secretions in the intestine digest food. Their ability to digest is directly related to water temperature. Mix equal amount of wheat germ with regular food in September. Gradually switch over to fish food containing wheat germ. It is more digestible.
The Koi do not eat when the water drops below 46 degrees. If you continue to feed it will just sink to the bottom where it will decay and pollute the water. Essentially your fish will go to sleep at 46 degrees. Their heart and breathing will slow down to where there is little or no physical movement. You must treat them accordingly.
When we get into the “spring-like” days of January and February it may be tempting to feed your Koi especially if you see them gathering on the surface of the water. Avoid this urge. Use your thermometer and check the temperature. Feed strictly by the thermometer and not the calendar and you will not have any problems. The temperature has to be above 46 degrees. If you load up their bellies with food and we get a fatal cold snap, it could wipe out all of your Koi. They cannot digest food in cold water.
Use a reliable water thermometer
Feed as follows by water temperature

 61 degrees+ Twice daily or more : Mix wheat germ fish food with your regular food
 56 – 60 degrees Once a day discontinue regular food and use just wheat germ food.
 51-56 degrees Two to 3 times a week
Switch to medicated food. Store in the freezer as you will use it again in the spring when pond water temperatures start to go up again The antibiotic will have no effect on your biological filter. Starting and ending the season with medicated food ensures that your fish sleep or wake up without any bacterial infections.
 46-50 degrees Once a week | With medicated food Do not feed again until spring when water temperature reaches 46 degrees…
 < 46 degrees  Do not feed

Watch water temperature in the spring. Reverse above temperature chart and start feeding fish food with medicated food when water temperature hits approximately 46 to 48 degrees. Followed by wheat germ, then wheat germ mixed with regular food.

Monitor ammonia, nitrite, nitrate and pH levels if you turned your pump and filter off for the winter. Be prepared to do water changes if ammonia is present in even the slightest amount.


  • REGULAR FISH FOOD (preferably Optimun/Impact)
    Cover plants if light frost is predicted. You may want to take the tender plants inside on frosty nights so that they can adjust to the inside environment. If weather permits you can move them back out the next day. We usually get a frost that will damage plants. Then we get a few weeks of Indian summer where the plants will continue to grow and help remove ammonia from the water. Covering them on frosty nights will prolong their usefulness and beautify the pond. Indeed, some pond plants have striking fall colors. When we get 40-degree nights, it is time to starting making permanent arrangements for your plants.

Clean up frost damaged foliage by trimming all foliage with shears or pruners even with the top of the pot. Drop the pots all hardy plants to the deepest part of the pond, where they will spend the winter. Move non-hardy plants inside for the winter

If you have a lot of plants that you plan to bring in for the winter, purchase one of those little plastic kiddy pools. Depending on your light situation, you may be able to place it near a real sunny window or sunny room inside for the winter. Or, set it up in a basement or other out of the way area. Add 3 to 4 ” of water to the pool. The plants do not need to have water over the top of the pot for this type of winter storage. If you do not have a sunny location, place plant grow lights over them with a timer and let the plants grow all winter long. Leave the timer on for 10-12 hours a day. You will have loads of plants come next spring!

Health Impact on Koi of VERY Cold Water: (Video)

Koi Fish Pond SuperCooling: What Is That?

Koi Fish Pond SuperCooling: What Is That?

SuperCooling, Common and Preventable


Supercooling – When you want a cup of coffee to lose heat, the fastest way is to pour it through the air from cup-to-cup until it has lost it’s heat.  

And in the same way a waterfall and fountain can propel your water through a thin-phase causing a convergence of air and water temperatures. This means that by day, your fish will warm faster because the water can pick up heat from both sun and air, but by night, the pond plunges down as the water gives up it’s heat passing through the water feature.

Here’s how the typical case appears. This is a true, documented case:

“This is real strange again. On Thursday a fish was laying on its side at the bottom of pond. For all appearances he was dead. But when I got the net out to retrieve him, he swam away. This is a 12″ Kohaku that is in my main pond outside….”

“An hour later he was back on his side so we netted him out and I did slides, 2 from gills and 2 from body. Nothing! The ammonia, nitrite and nitrate are all zero. Ph was 8.2 which is normal for me. Water temps was 38 degrees. …”

“I put him in a 20 gallon tank inside and let the water warm up from the 38 degrees to about 62 on its own. He swims upright and does not lay on his side at all now that he is inside. There are no marks, ulcers etc anywhere on his body. Gills are bright red in color. He acts totally normal now that he is inside. Swimming and staying upright. My hubby said maybe he just wanted to come in from the cold so that is why he was playing dead. Surely that cannot be the answer!”

“We are having and been having big temp swings the past few weeks. I have been feeding Impact every few days if the water temperature warrants feeding….”

“This morning the outside water temp was 42 tonight at 6 PM it was 53.”

“The water fountain (3900 cal pump) shoots the water up 10 feet so it is not an oxygen problem…”

“The thing that bothers me is the 4 fish I lost in March did the same thing, they just laid on their side and moved when you tried to net them. They eventually died.”


“There’s the whole answer:

‘We are having and been having big temp swings the past few weeks. I have been feeding Impact every few days if the water temperature warrants feeding…..The water fountain (3900 cal pump) shoots the water up 10 feet…”

When fish are rapidly chilled they lay over. Laying over is seldom  more than a clinical manifestation of shock/severe stress.
When brought and slowly warmed up, they usually recover, but they ought to be injected with antibiotics at least once, or they will die a week after warming up. This is because the bacteria will traverse the gut when the fish is nearly frozen and proceed to kill it later.

Do not feed when you think, or even imagine, there’s even a 2% chance of dropping below fifty degrees (F) within three days of feeding..

This fish should survive, but you should evaluate for things which may cause “supercooling”. Waterfalls and fountains can make water and air temperatures parallel, which means that when the air temperatures plunge and your waterfall is running, so shall the water temps fall, and when air temperatures warm by day, if there’s a fountain or waterfall running, so shall the water be warmed, and thence when the air temps fall by night, so shall the water temperatures fall, and thence the fishes will layeth over….I need a cup of coffee…it’s early.”

Best Regards,

“Doc Johnson”


  • Maintain water circulation at all times but when the temperatures are dropping, the circulation should be gentle and minimally break the water surface.
  • To keep water moving under the surface, disturb the top HALF of the pond water only. For example, do not put the circulating pump on the pond BOTTOM – allow the bottom depths to remain minimally disturbed when it’s cold out. Circulators could be halfway down in the water column.
  • Do not feed when you think, or even imagine, there’s even a 2% chance of dropping below fifty degrees (F) within three days of feeding.. Exceptions would include those areas (Portland) where water temps do drop below fifty but never below forty..
  • When temperatures are climbing, you can employ any feature desired.
  • When ice is a threat, you may maintain a hole in the ice for gas exchange with a cattle trough heater (35$) which will NOT disturb pond hydrology or cause turnover in the water layers.
+ “Supercooling theory can be of some benefit if strategically used in the cool of the night or the heat of the day depending upon what your water temperature goal is. Running your pumps during the day can absorb heat and turning them off at night can conserve it.” Doc Johnson
+ Note From Doc Johnson
In the winter, I just run a circulating pump for underwater circulation, and I return my filter under water as well to minimize surface disruption. I do not remove water from the deepest part of the pond, preferring instead to let that water remain still for fish rest.” Doc Johnson

Koi Fish Pond SuperCooling: What Is That?

Water Changes for Health, and Ammonia Control

If fish are suffering illness due to any obvious deterioration of water quality, you are well advised to begin a systematic daily changing of 20-40% of the total volume in the system.

There are some important points to consider before going out and wholesale changing the water.

First, make sure the water change does not radically change the temperature of the system.

Secondly, be sure that the water change does not result in truly electrolyte poor water. One test of this is the Total Alkalinity, but other salts are important as well. It might no hurt to add a teaspoon of salt per gallon of water in any major water change where live plants are not being maintained. This will ease the stress of the change on the fish and stimulate the production of a healthy, protective slime coating.
Scaleless fishes will not be harmed by that salt dose, the salt to use would be either non iodized table salt or sea salts.

The final consideration in doing daily, massive water changes, is to be sure the pH is not fluctuating wildly with each change. Does the tap water resemble the pH in the system?

Water Changes for Health, and Ammonia Control
Water Changes for Health, and Ammonia Control

As a side note, be careful about adding all sorts of fancy water conditioners to the water. For example, the product that rhymes with Press Coat is a synthetic agent that coats the fish with a protective coating. Neat. But consider that until it is reformulated, it will be a detriment because the gills are coated as well. This can complicate respiration where the gills were not functioning beautifully to begin with.

Another set of chemicals are sold to bind Ammonia. They use aldehydes to accomplish this feat. The aldehydes can accumulate and become caustic to fish if no ammonias are actually present. They are useful, but should be used sparingly and judiciously.

So, to re-cap, change 20-40% per day, watching temp and supporting Total Alkalinity and electrolytes. Consider adding a teaspoon of salt per gallon with the changes, and finally, don’t go overboard on the water conditioners.

On the long term, Constant Inflow Water Changes are a good idea. Installing a “drip irrigation system” TO a pond or tank brings SLOW inflow of new water, and a simple overflow device (overflow box) lets water leave the system. Ideally, you would replace 10-20% of the system volume per week. This is a VERY low flow taken on the 24hr x 7d cycle. No dechlorinator is needed.

The pundits will attack the assertion that ‘no dechlorinator is needed for drip irrigation water changes’ BEFORE they do any math on just how much “New” chlorinated water is in the system at any given time. (Drip Irrigation Water Changes)

Dr ErikJohnson

Carbon Dioxide in Aquaria and Ponds

Carbon dioxide is produced by the respiration (not photosynthesis) of both plants and animals. When you exhale, you produce Carbon Dioxide. Pretty much the same with fish except they don’t have bad breath like you do. Just kidding.

One interesting thing about water is that Carbon Dioxide levels can exist independently from the Oxygen concentration. For example, you can have water with plenty of Oxygen, but which also has a lot of Carbon Dioxide.

Carbon Dioxide in Aquaria and Ponds

Carbon dioxide has a partial pressure in the air, when oxygen goes up, carbon dioxide has to go down. In water; NOT SO. You can have crazy CO2 levels with high O2 levels and vice versa or any mix.

Carbon Dioxide in Aquaria and Ponds
Carbon Dioxide in Aquaria and Ponds

Carbon dioxide likes to do one thing in water. It likes to convert to carbonic acid. When it does this, it tends to affect pH by bringing it down into the acid range. So, a bunch of fish breathing in a small tank with minimal circulation and surface agitation may actually accumulate sufficient carbon dioxide to drag down the pH due to the carbonic acid equilibrium that will result.

Removal of carbon dioxide (with its carbonic acid behavior) by increasing surface exposure and gas exchange will remove the carbonic acid and may raise the pH above neutral.

Do you remember in the discussion of Ammonia when I mentioned that Ammonia is more toxic at a higher pH? Well, this created a problem for some fish once. Someone had the idea that if you deprive the fish of aeration, you will preserve a high carbon dioxide level. The carbon dioxide level will keep a higher carbonic acid level, which will keep the pH down. The lower pH will ionize the Ammonia to Ammonium and preserve the fish from Ammonia damage at shows.

So, at least for a while, it was a widely perpetrated myth to enjoy gasping fish at shows, and use autogenous Carbonic acid to lower the pH, rather than do a water change to remove the threat from Ammonia.

The most amazing myth: “Don’t oxygenate Show Tanks” because it blows off carbon dioxide [carbonic acid], raising the pH and causing the ammonia to become more toxic.

Live Plants and Koi For Algae Control

Koi and plants do fine if the plants are abundant enough. If you “try” one or two plants to see how it goes the group of Koi will consider them quite the novelty and will probably allocate a lot of time to checking them out. Not having thumbs, they experience their world with their mouths.

If there’s ANY gravel in the pond, they will spend time sifting that, and rolling the rocks around, and playing with the plants, and then the plants aren’t the sole entertainment.


Veggie Filters: Algae Control Naturally

The prime competitor to algae is simply other plants. All pants consume nitrogen and phosphorus and iron. So, if there are abundant live plants in a system, what’s an algae to eat?

“Hey the plants are hogging up all the nitrogen!” (they whine bitterly)

Veggie Filters: Algae Control Naturally

So if there’s a handy way to put plants in the water column, DO IT. Some people simply put the plants in the pond. If you put enough in, the Koi pick on them a little, get used to them and then cohabit.

Other people net off a section of the pond and put plants in there. That’s how we set up Jimmy Carter’s pond (yes I officially care for his pond and have met him and Rosalyn) at the Carter Center in Atlanta and we just netted an area and loaded it with Hyacinths and Lettuce in the Summer and then Anachris in the Fall. (Year round nitrogen reduction)

Some people make an entirely separate vat of plants and move some water through at all times. This is much the same as bogging plants, as well.

Finally, I made some floating crates pictured above. The crate material are polyethylene floor grates for slaughter houses and such; cable tied together in the form of boxes they float and the plants are in there. Click the image above for the larger version for study.

controlling algae with live plants how to make a veggie filter

plant filters for algae control vegetable filtrtation

Algae Control: Green Water Algae Bloom

Algae Control, Green Water Bloom.

This is an old video with good, current information. Crude in it’s cinematography, but full of good information.  Greenwater is basically just that: Green Water which obscures your view of the fish, but is healthy. It is a product of nitrogen fuel, fish, sun and a failure to have competition from live plants. Chemistry is not the cure. You will do well with a pen and paper as the video presents a lot of information FAST.

Why Algae Matters: Green Algae Blooms

Algae matters because it can obscure your view of the fish and also, string algae can choke a filter.

Good Reasons Algae Matters

  1. Well Algae seems to have some sort of healing effect on fish, whether that is actually a function of “A good home for algae is a good home for fish” or the algae actually provide some sort of consoling cover, or even a healthy nutrient base….Unknown, all good theories. I am sure the pundits know for sure, based on zero research; but careful reading of Grainger’s Electronics and Machine Parts Catalog. (That’s an obscure joke about how awful the extrapolation with some people can be)
  2. Algae oxygenates.
  3. Algae consumes excess nitrate and phosphorus. As some people know, high Nitrate levels are eventually immune suppressive if only as a chronic stressor but equally likely, as a cause of perpetual vasodilation. (injected, veiny fins)
  4. String algae produces what are known as “plant agglutinins” which are ‘sticky proteins’ which bind organic macromolecules and bacteria into large pieces to settle out, ostensibly dropping the particles to a position closer to the plants to be used by their absorptive structures. (Yes, plants have “arrows” to collect their “prey”
Why Algae Matters: Green Algae Blooms
Why Algae Matters: Green Algae Blooms

Why String Algae Matters

  1. Koi will eat String algae except if better food is around they might leave enough to be ugly.
  2. String algae breaks off and spreads and it can glut a pond
  3. String algae breaks off and goes to the filter pump and other filtration structures (the mechanical elements) and pretty much stops it.
  4. If the pH drops a lot, the string algae will die and being a fairly massive plant mass, it will create surplus decay products (nitrogen) and will contribute massively to water quality deterioration even after the pH is corrected.

Why Greenwater Matters

Same thing;

  1. If the pH drops a lot, the string algae will die and being a fairly massive plant mass, it will create surplus decay products (nitrogen) and will contribute massively to water quality deterioration even after the pH is corrected.
  2. Greenwater is not-nice because you got the pond to watch your fish, but noo-o-o-o-ooo not with greenwater.
  3. Worse, greenwater stops you from being able to monitor the occurrence of disease, but also to monitor improvement of diseases you already know about.
  4. A large dose of certain medicines can kill alot of greenwater and again, that die off can contribute massive amounts of nitrogen waste as well as consuming enormous amounts of carbon dioxide and oxygen consumption.

What Is Algae?

Algae are single celled plants. They occur in primarily two forms, one form composes strands which can get so long they appear as “hair” or string and is referred to as “String Algae”.

Fortunately, String Algae is very, very easy to control.

What Is Algae?
What Is Algae?

The second form of algae is a bloom of the single celled free floating type, such as the tiny plant above as seen under the microscope. When you get an algae bloom in your pond, the fish disappear in the green soup.

Algae, as plants go, hardly differs from regular plants on your desk. During the day when the sun shines on them, they MAKE oxygen and consume carbon dioxide. Cool, for the water and the fish.

But at night it’s different. At night the algae CONSUME oxygen and produce carbon dioxide. That’s bad for the fish.

But; most of the time, algae consumes NITRATES, which is good. They use nitrates to grow and live. So in order to keep nitrates down, or, if your nitrates get high, greenwater or other algaes are the solution and the result.

Here’s why algae matters. It differs from one form of algae from another. String algae is one kind of problem and green water is another.

Tannin Stains or Yellow Water and It’s Treatment

My pond is about 3 months old. The water is clear but has a yellowish tint that I would like to get rid of. I have koi and water plants in the pond. All my water tests are fine except the water seems to be ‘hard’ and the pH is about 8.5 in the afternoon. What could be causing the yellowish tint and what product do you have to correct it?

There are at least three places “yellowing” can come from and they are NEVER good for fish.

Tannin Stains or Yellow Water and It’s Treatment

If Ammonia accumulates sufficiently, it can cause a yellow cast to the water. Of course, this is easily tested – and not the most common cause of water-yellowing.

Leaves which fall into the pond will decay and cause yellowing. This is the release of tannins – which are astringent for fish. They are NOT terminal, or deadly, but they represent deterioration of water quality which especially makes fish more vulnerable to disease organisms.

Tannin Stains or Yellow Water and It's Treatment
Tannin Stains or Yellow Water and It’s Treatment

The most common cause of yellowish casting of the water is plants and their pots, or bog gardens which share water with the main pond. This is the most common and the worst cause of yellowing in the water. Basically it’s a “tea” being made with your pondwater percolating in and around the dirty root ball of the plants. Soil tea. The tannins (and humic acid) leeching from the soil in a bog will control green water. It will also decrease the pH in the system. Sometimes that’s a bad thing, sometimes it’s good.

It’s important NOT to let bogs stagnate. In some bog gardens, there are numerous decay processes which liberate noxious gases, carbon dioxide, and which consume dissolved oxygen. Stagnant bogs also contribute unnecessarily to the elevation of dissolved organics – background pollution. In other words – stagnant bogs are bad. Keep the water moving through the bogs. It’s better for the plants and it contributes to nitrate reduction. The roots of many bog plants contribute plant agglutinins to the water which makes it healthier and drops virus and bacterial counts.

Note: 2008 Spring –  All ponds need water changes. The more fish and fish wastes, and sometimes, the better the filtration – the more important water changes become. I’ve been using 1/8th inch ID irrigation line to supply my various ponds and tanks with constant inflow of fresh water as a form of 10% per week all the time water change. I’ve written that up on this web site.
Anyway; not all bogs are bad. Some are crafted from gravel with an intentional and uniform “upflow” or “downflow” limnion and are well engineered for filtration. These gravel bogs may have abundant plant material PLANTED IN THE GRAVEL – not in root balls. I have several of these set up and I am ENTHRALLED with their performance.

Potted plants can leach tannins and other amber colored contaminants from their soil into the pond. These are almost as hazardous as bog effluents. Folks are highly recommended to repot their plants in large sized aggregate gravel, and replant the plants every year to minimize the development of anaerobic decay conditions in the pots.

Please do not allow your water to become or remain yellow.

Water testing can rule out Ammonia’s contribution to yellow stained water.

If Tannins are incriminated, remove all leaf litter and take your bog gardens off line or improve the bogs’ through flows and eliminate stagnation – leaving the pond to have it’s own clear clean well oxygenated water.

Finally, a major water change will remove most of the yellow color.

If major water changes are not feasible, then you can use carbon to control the yellow color. Carbon is a black aggregate media which is made from superheating organic materials like coconut shell and wood as if in a kiln, except in the absence of oxygen. The product is black and light in weight.

After rinsing, the carbon can be put in a nylon mesh bag and placed directly in the water flow. It is NOT as effective to put the carbon in your waterfall because even though the water is moving rapidly, it’s not moving THROUGH the carbon bag. This takes some engineering. If you can get ALL your water through a pump in three hours, and that pump goes through a five gallon bucket half-full of carbon in mesh bags without channeling or bypass, you will see gin-clear water in two days. The idea is that ALL the water is PUSHED THROUGH the carbon. Not just over it.

Carbon expires rapidly, in direct proportion to the organics in the system. If the system has a lot of tannins – the carbon will expire on the order of days. After replacement, with cleaner water the next bags of carbon will last longer.

Unsure if the carbon still works? Simply take some and put it in a glass of water. Add a couple drops of Methylene Blue. Check it again in the morning. If the MB is gone, the carbon still has some “life” in it.

Hydrogen Peroxide to Reverse Potassium Permanganate in Koi Ponds

After a potassium permanganate treatment, you can turn the water back to crystal clear. Be careful though, treating with peroxide prevents the successful deployment of Potassium permanganate the following day!

Hydrogen Peroxide to Reverse Potassium Permanganate in Koi Ponds

Hydrogen Peroxide is applied the the complete CONCLUSION of a potassium permanganate treatment. The reason is: that you do not want interference with potency of potassium treatment on subsequent days, so, if possible; wait until you are finally DONE with potassium before treating… However, if the water is OPAQUE brown – and you cannot see the fish, you need to decolorize at once and sacrifice the next few days’ treatments. When potassium permanganate turns the water to mud it’s because there was a monumental amount of solid background pollution that was incompletely oxidized. It marks the end of all safe deployments of potassium permanganate.

Regular hydrogen peroxide from the grocery store is used. DOSE: One quart of HYDROGEN PEROXIDE 3% per five THOUSAND gallons of water.

Hydrogen Peroxide to Reverse Potassium Permanganate in Koi Ponds
Hydrogen Peroxide to Reverse Potassium Permanganate in Koi Ponds

Just so you know, our initial dosing for potassium-reversal was done at a mammoth level: One CUP per one hundred gallons, and we used like six gallons in a five thousand gallon pond with safe results, BUT, and this is a big but; testing to determine the MINIMUM dose needed brought the effective successful dose down to the 1quart/5000G level.

Decolorization requires up to an hour depending upon how your pond circulates, how much KMnO4 is in there, and how much peroxide you used..

Remember that your potassium will fail the next day or two.

If you attempt to overdose and “beat” the previous day’s peroxide, you WILL kill your fish. So, don’t decolorize with peroxide until you’re REALLY done with the KMnO4 –