The poisons, Chlorine, Chloramine, and Pollutants

by Norm Meck
Koi Club of San Diego
© 1996

Chlorine

Measurement:

Chlorine (Cl), measured in ppm, is a gas which has been added to tap water to control harmful bacteria. City provided tap water is normally found to have 0.5 - 3.0 ppm but higher surges are sometimes observed. Some city water supplies can still be found that either do not require chlorination or may have the chlorine removed before the water is distributed. This would not be of concern to those who take their tap water directly from a private well. Droplet, powder, and pill colormetric test kits are available. Recommended test kit range 0 - 4 ppm. A chlorine test kit is not considered necessary for the average pond.

Acceptable range 0


Effects:

Chlorine is a quick killer in fairly low concentrations (less than 0.5 ppm). Even in very small concentrations, it burns the edges of the gills with long term after effects. It also can be deadly to the bio-converter bacteria.


Treatment:

In an open container, water will release about 1/4 of the chlorine concentration per day to the air . Water that has set in an open container for a week or just for a couple days if heavily aerated, is normally safe to use or better yet, pretreat tap water with one of the commercial chemical products. Follow the manufacturer's directions. (Or make your own)


Homemade Chlorine Neutralizer

Make a solution consisting of 4 oz (1/4 lb) Sodium Thiosulfate crystals (technical grade) dissolved in 1 gallon of distilled water. Use 5 ml (1 teaspoon) of the solution per each 10 gallons of makeup water to neutralize up to 3.75 ppm chlorine. One measuring cup full can be used for each 500 gallons. (The entire gallon of solution will treat about 7500 gallons of tap water.) The shelf life of the solution is about six months when stored in a cool location. The sodium thiosulphate crystals will keep for several years if kept dry..


When pre-treating replacement water, the dosage is for the quantity of water being replaced, not the total pond capacity! Although it would be better to treat all tap water being added, small amounts of replacement water without dechlorination treatment are often added without noticeable effects to the fish. It is recommended that any time more than one percent of the pond water is being added, it be treated. Do not use chlorinated tap water to clean your bio converter (filter) media unless you are actually trying to sterilize it. Water from the pond is a much better choice for this task.


Chloramine

Chloramine is a compound of chlorine and ammonia that also may be added to tap water to control bacteria. It can also be formed by adding water containing free chlorine to a pond containing ammonia. If any ammonia is present in a pond, be sure and treat it before adding any tap water containing chlorine. Chloramine can be detected using the same test kit used to test for ammonia. Chloramine is difficult to measure quantitatively in low concentrations, and particularly when a combination of chlorine and chloramine are present.

Acceptable range 0

Chloramine does not decrease concentration nearly as fast as chlorine when exposed to air. It produces the same general effects as chlorine but is usually found in the lower concentrations that result in long term damage to the fish. The same treatment actions as for chlorine apply except that the ammonia remains after neutralization. A "healthy" bio-filter will take care of the ammonia or a chemical treatment may be used. Some commercial products incorporate treatment to neutralize both the chlorine and ammonia components at the same time. Check the manufacturer's directions.

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Pollutants

This catch all category of Pollutants means anything added to the pond that is not wanted in the pond. Pollutants can consist of items which may or may not be harmful to the fish and they may or may not be visible. They may float on the surface, sink to the bottom or dissolve into the water. They may come from outside the pond or from within the pond itself, i.e. oil leaking from a submerged pump. Some pollutants are easy to identify and control and/or remove, i.e. leaves, pollen, dead rats, etc. Some just add to the filter load if not removed but cause little other problems if not in excessive amounts, i.e. bird droppings. Most of the harmful pollutants that dissolve into the water are hard to identify or quantify. Surface water runoff that can enter the pond is often a major source of pollutants. This is why all ponds should be designed with a raised edge or at least some type of channel around them so that the surface water will not enter the pond. Other than preventing pollutants from being introduced into the pond, they can only be controlled through water change out procedures.

Here in sunny southern California, where we get very little rain, heavy buildups of "stuff" on the covers, shade cloth, or trees hanging over our ponds often occur. When it does rain, all of a sudden there is a large amount of this material that is washed off and added to the pond water with possible detrimental effects. (We are all familiar with oil coming up from the roadways during a rain following a dry spell and how the cars go slip-sliding down the interstate.) If the material overhanging the pond is rinsed off with a hose every couple of weeks, then the individual additions are much smaller and are more easily controlled through the routine water change outs. This rinse down of overhanging material should be part of each pond keeper's weekly or at least biweekly pond maintenance during dry spells..

Toxic Plants

One pollutant area that is often overlooked by pond keepers has to do with the plants in the pond or those that are part of the landscaping around (and over) the pond. The seeds of many plants can swell and plug up the digestive tract of the Koi. A partial list of the plants or parts of plants that have been reported as toxic to Koi for various reasons include:


Amaryllis - bulbs
Baneberry - berries, roots
Bird of Paradise - seeds
Black Locust Bark - sprouts, foliage
Boxwood - leaves, stems
Buttercup - sap, leaves
Calla Lily - leaves
Cherry - bark, twigs, leaves, pits
Coral Plant - seeds
Daffodil - bulbs
Datura - berries
Death Camas - all parts
Eggplant - all but fruit
Elephants Ear - leaves, stem
English Ivy - berries
Foxglove - leaves, seeds
Hemlock - all parts
Holly - berries
Hyacinth - bulbs
Indian Turnip - all parts
Iris - bulbs
Jasmine - berries
Java Bean - uncooked bean


Lantana - immature berries
Laurel - all parts
Locoweed - all parts
Marijuana - all parts
Mayapple - all parts
Mistletoe - berries
Mock Orange - fruit
Morning Glory - all parts
Narcissus - bulbs
Oak - acorns, foliage
Pine - sap
Poinsettia - leaves, flowers
Potato - eyes, new roots
Privet - berries, leaves
Prunus varieties - seeds, some parts
Redwood - sap (from decks also)
Rhubarb - leaves
Ranunculus - all parts
Snapdragon - all parts
Snowdrop - all parts
Tiger Lily - all parts
Tomato - leaves
Tulip - bulbs

Have you identified all the plants in, over, and around your pond?

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Water Change Outs

Partial water change outs can reduce the amount of anything dissolved in the water but not totally remove it. Although it is sometimes necessary, draining and refilling a pond should only be used as a last resort! Do not use large water change outs to clear green water conditions. A large water change out will normally make the situation worse, not better. Often, several partial water change outs, performed over a period of days or even weeks, can reduce the concentration of an undesired item to acceptable levels without serious after effects. A water change out reduces the amount of a substance in the water by the same amount as the percentage of water replaced. Remember the concentrations of any "good" stuff in the pond is being reduced at the same time as the "bad" stuff. Also the water being used for replacement may have undesired components as well.

A water change out is considered to be when a measured amount of water is drained from the pond and then replaced. Just adding water and letting the pond overflow will not accomplish the desired results unless significantly more water is transferred. Water added to replace that lost by evaporation is not part of a change out.

Example:
It is desired to decrease the Salt in a pond by one half. Any of the following will have the same approximate result:

Depending on the urgency to carry out the action, the largest number of change outs over the longest time would be the best approach.

Unfortunately, this does not apply in the same way to pH. The change in pH for a given water change is dependent upon the Alkalinity and pH in the pond as well as the Alkalinity and pH of the replacement water. Adding water with a higher pH than the pond water will raise the pond water pH but it is difficult to predict how much. Remember that if the water being added to the pond has a pH higher than that of the pond, make sure any ammonia in the pond has been treated before adding the new water.

It is considered appropriate to change out from 5 to 10 percent of a pond's water per week. A small pond (500 gallons or less) should receive the 10% weekly change out. The 5% change out is appropriate for a large pond (5000 gallons or more). Any water replaced after a weekly backflush of a filter system or other maintenance actions should be included as being part of the weekly change out amount.

When making the water replacement with tap water that contains chlorine or chloramines, it would be better to pretreat the water with the chlorine neutralizer before adding it to the pond (particularly small ponds). If this cannot easily be done, use a fine spray of water over the pond and divide the total computed neutralizer dosage into two to four parts and add while the makeup water is being added. Don't Forget To Turn Off The Water! Set a timer or something to remind you that makeup water is running into the pond. Inexpensive flow timer shutoff devices that hook directly on the hose are available and are a good safety item to use.


Final Thoughts

Keep good records of your pond. A chronological log of chemical test results, treatments, maintenance actions, water change outs, and even addition or removal of fish can help determine the cause (and required treatment) of a future problem. I keep mine in a computer file but just a simple notebook is all that is needed.

Keep chemical test apparatus clean. Scrub out the test vials periodically. Just rinsing with pond water doesn't get out all the residue buildup. Whenever you buy a test kit, write the purchase date on it. If not otherwise stated on the test kit, replace any liquid based test kits every year. Replace the sealed packet dry powder and pill based kits every two years. Be careful about anything that you put in your pond. Know your pond capacity and carefully calculate and measure dosages . Know what you are treating for; it is usually better not to treat at all than to dump in something because you think there might be a problem. Second only to ammonia poisoning, more Koi have died from improper treatment with medicines and chemicals than for any other reason.

Many times, the first indication of a problem can be detected by simply watching the behavior of the fish. Changes to their normal activities means it is time to get out the test kits. This is the best part of having the pond anyway so spend some quality time with your Koi and get to know them.


If you would like a printed, bound booklet copy of this entire series (plus some additional information) for handy reference, send a check or money order for $10 to:

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Comments ? Questions ?

normeck@pacbell.net


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Copyright © 1996, Norm Meck, Revised October 6, 1996