All you need to know about pond water quality
  • ZackZack October 2012
    Posts: 232
    Pond water quality is defined by what the water contains and in what amounts: dissolved oxygen, fish wastes and dead matter, as well as their associated byproducts (ammonia, nitrites, nitrates). Koi experts recommend the monitoring of the following water parameters once a week (or at the minimum, once a month): ammonia level, nitrite level, nitrate level, and pH. The monitoring should be more frequent if the pond is newly built, since the pond's water quality has not yet stabilized. Pond temperature must also be monitored regularly if temperature extremes are being experienced by an outside pond.
    One rule that any novice koi hobbyist must know from the start is that water quality can never be judged by water clarity. Some ponds with crystal-clear water may be lethal to fish, since it was lethal enough to prevent algae from growing in it. On the other hand, green ponds where you never see the fish can be very healthy to its inhabitants, producing koi that are bigger and more colorful. Given this, the only way to assess water quality is to test it.
    Pond water quality is tested using water testing kits. Normally, every parameter requires its own kit, so the pond owner should be ready to buy 4-5 test kits to be able to test the basic parameters.

    Water Quality Parameters

    Nitrate: Ideally at < 80 ppm. Limit to max 200 ppm.

    Nitrite: Ideally at 0 ppm. Limit to max3 ppm.

    Hardness: about 100 ppm. Limit at 50 ppm min./150 ppm max.

    pH: Ideally at 7.2-7.6 Limit at 6.5 min./8.2 max.

    Excellent pond water quality is achieved through proper filtration of the pond water. Filtration is the process of removing waste products and other harmful compounds from the water. This can be done mechanically, biologically, or chemically (not recommended). Good filtration systems combine mechanical and biological filtration techniques to achieve its goal: clear and clean water. Water is usually drawn or impelled into the filter using an adequately-sized pump. The 'dirty' water undergoes 'cleaning' as it passes through the various stages of the filter, until it is returned to the pond in purer state.

    Mechanical filtration consists of physically trapping the particulate wastes and debris in the water. Sand, beads, pads, and brushes are the commonly used materials for mechanical filtration. Passing the water through these materials traps whatever suspended materials are in the water, e.g., leaves, twigs, fish feces, etc. Mechanical filters become more effective if set up in two or more stages, with earlier stages designed to trap larger debris than later stages. Mechanical filters are often used as the first stage(s) of the filtration system since they prevent the 'larger' wastes from reaching the biological filters.

    Biological filtration, as the name implies, employs natural biological processes to convert harmful waste byproducts into less invasive compounds. Koi excrete ammonia, which is deadly to koi in large doses. Certain anaerobic (non-oxygen-breathing) bacteria convert ammonia into nitrites, which are, unfortunately, also poisonous to koi. The good thing is, there are 'good' aerobic (oxygen-breathing) bacteria that convert nitrites into nitrates, which are no longer deadly to koi. These 'good' bacteria are also known as nitrifying bacteria. Nitrifying bacteria occur freely in nature, and will populate your pond in time. Biological filtration therefore simply entails providing a good filtration medium (one with as large a surface area as possible) for these good bacteria to grow in.

    Chemical filtration refers to the use of water clarifiers and algaecides to 'clean' the water. This may be used as a one-time fix or treatment of the pond only or as an integral part of the filtration system to maintain certain chemical properties of the pond water within specifications. Some koi experts believe that treating ponds with chemicals to clean it is not advisable. In fact, chemical filtration can be avoided altogether simply by setting up a good mechanical/biological filter system complemented by regular water changes.

    Water quality, as said many times before and to which we all agree, is the most important factor in the pond that affects koi health (and happiness). The question, therefore, is not on the importance of diligently keeping our pond water clean, but on how well we know if we're meeting the requirements. Unless we have a way of measuring the cleanliness of our pond water, we can not really claim that we have good water, regardless of how frequently the mats are cleaned or how clear the water is. Water testing kits, which are now widely available in the market, should therefore be part of any koi hobbyist's toolbox.

    Koi experts agree that water is good enough for your koi if: 1) it is free of chlorine and other chemicals such as pesticides, heavy metals, organophosphates, etc.; 2) it has undetectable levels of ammonia and nitrite; 3) its hardness, pH level, and temperature are correct; 4) it has low levels of dissolved organic compounds (DOC) and particulate organic compounds (POC); and 5) it is stable in its quality.

    If you get your water from the tap, then chances are that it has been treated with chlorine. Chlorine, even at the level present in tap water, is deadly to koi. Thus, you must never put koi in pond just filled with chlorinated water. 'Aging' the water by 24 hours prior to putting your koi in is one advice that you can follow. Later additions of tap water may be done as long as they're small in quantity compared to the bulk of your pond water. Testing of chlorine level after each addition is highly recommended.

    Ammonia (NH3) is the next deadliest contaminant in pond water, next only to chlorine. One part per million is already detrimental to the fish. The main source of ammonia, unfortunately, can not be removed from the pond. This is because ammonia in the pond comes primarily from the koi themselves. Ammonia will therefore always be present in the pond as long as there are koi (or other fishes and animals) living in it. The good news is that ammonia is easily converted to less harmful compounds by certain types of bacteria (nitrosomonas) through biological filtration.

    The threat of ammonia contamination poses the highest risk while the pond is still new. This is because new ponds still lack the colony of 'good' bacteria needed to convert ammonia into less harmful compounds. Koi experts recommend daily checking of ammonia levels and daily 50% water changes in new ponds until ammonia readings stabilize. The threat of ammonia in new ponds is so serious that there's even a name for this phenomenon - the 'New Pond Syndrome', or NPS.

    At low levels (below 0.1 mg/liter), ammonia acts as a strong irritant to the koi, especially to its gills. Flashing may be exhibited by koi irritated by low levels of ammonia. Higher ammonia levels can lead to skin and gill hyperplasia. Gill hyperplasia refers to the condition wherein the secondary gill lamellae become swollen, resulting in breathing problems for the koi. Serious gill disease and death can occur if the lethal levels of ammonia contamination are reached.

    The acceptable ammonia reading for koi ponds is, well, zero. Thus, your pond is threatened by ammonia as long as your test kits are able to detect ammonia in your water.

    Sooner or later, the rate of ammonia level build-up in a new pond will decrease as biological filtration does its job, but another toxic compound will be taking over as this happens. Ammonia is converted by the nitrosomonas bacteria into nitrites, which are also harmful to the fish, but not as deadly as ammonia. Nitrite levels therefore shoot up as the ammonia levels go down in a new pond.

    Nitrites (NO2) at low levels can subject the koi to stress, making it vulnerable to diseases caused by other factors. High levels of nitrites cause skin and gill epithelia damage, which can lead to parasitic invasion or secondary bacterial infections. Fish suffering from nitrite poisoning will be gasping at water surface and stay around water outlets. Water testing kits must register nitrite readings of zero as well if the water is to be considered nitrite-safe. Unsafe nitrite readings can be corrected by sufficient partial water change. Adding salt to the pond (around 0.02%) also makes nitrites less toxic to koi, since their gills will tend to take up the added chloride ions instead of the nitrite ions, getting protection from the latter.

    Eventually nitrite readings in a new pond will go down, just like the reduction of ammonia levels before it. Again, the reason for this is the conversion of nitrites into nitrates by 'good' bacteria, this time the nitrobacter sp. Nitrates are significantly less toxic than nitrites, but they should still be included in regular water quality checks.

    Nitrates (NO3-) are generally harmless to koi, although koi had been observed to lose their appetite if the nitrate level is allowed to go unchecked. Nitrate level should always be kept under 60 parts per million (ppm), which is equivalent to 60 mg per liter, although some koi experts say that a nitrate level of 100-500 ppm is not yet detrimental to koi. Partial water change is a good remedy to higher-than-normal nitrate level. The use of plants and trickle filters will go a long way in stabilizing the nitrate level of the pond.

    A weekly test for ammonia and nitrate levels is recommended, although this frequency may be diminished if the pond has matured enough and stable readings are already being taken consistently. Nitrate level testing can be done only once a month. Of course, any change in the filtration system or koi pond itself necessitates a more frequent regular monitoring once more until the readings stabilize again.

    Copper and iron are examples of metals that are toxic to koi. Be sure that your pond water is not exposed to these metals. Possible sources of copper and iron are your piping system, heaters, and even your filters.

    Koi pond water pH is another water quality parameter that needs to be checked regularly. The term 'pH' stands for 'pondus hydrogenii', and is a measure for how acidic or basic your pond water is. A pH of 7 means that the water is neutral. As the water becomes more acidic, the pH number goes down. The pH number goes up as the water becomes more alkali. Koi pond water pH must be maintained between 7 to 8.5.

    Off-scale pH readings can result in direct physical damage to the skin, gills, and eyes of the koi. Prolonged exposure to incorrect pH can lead to stress and in extreme cases, epithelial hyperplasia (swelling of the gills) or even death.

    Water hardness, on the other hand, measures the mineral (calcium, magnesium, iron, zinc, etc.) content of the water. These minerals are usually brought into the pond by rainwater that has percolated through rocks. There are two hardness numbers usually monitored in koi ponds, i.e., the KH (for carbonate hardness) and the GH (for general hardness).

    The pond's KH level (also known as the alkalinity) determines its pH buffering capability, or the ability of a pond to keep itself from becoming too acidic. The pH of a pond is affected by a lot of things (such as plant photosynthesis and the production of acids during nitrification), and can swing in value from time to time. One way to stabilize the pH of a pond is by neutralizing any acids introduced into the pond with carbonate and bicarbonate ions, a process known as buffering.

    GH is just the sum of KH and another hardness parameter, the permanent hardness. In a koi pond, the permanent hardness is negligible compared to the KH, so GH and KH may be treated as one for practical purposes.

    In most water systems, water hardness (GH or KH) is quantified in terms of the amount of calcium carbonate (CaCO3) in the water (mg per liter or ppm). Very hard water contains greater than 300 mg of calcium carbonate per liter of water while soft water contains less than 75 mg per liter. Koi ponds, according to koi experts, should have a water hardness of 100-150 mg CaCO3 per liter of water, or 100-150 ppm.

    Soft pond water should be avoided because it forces the koi to exert more effort in osmoregulation, the process of maintaining internal body water concentration to the correct level. Furthermore, a low KH results in pH instability, which can be lethal in extreme cases of pH swing. On the other hand, mineral deposits will form in the pond if the hardness exceeds 150 ppm. Note that some koi experts advise higher hardness levels than this (even up to 300 mg), if only to assist the fish in osmoregulation.

    Water to us is something to drink, take a bath with, or swim in. To our koi, however, it is what they breathe and live in, what dictates their bodily functions and, ultimately, what determines whether they will live or die. Indeed, koi pond water quality is something that every koi enthusiast must never take for granted.
    My kois are my lover
  • nocturnalnocturnal October 2012
    Posts: 376
    thanx for sharing bro Zack :)
    a great article that i've read when i started to go seriously into the hobby back in 2008 :)
    before that only kept local kois in an 8'x4' FGT :-D

    IMHO out of respect and courtesy to the author, Elmer Epistola, u need to acknowledge where u copy & paste the article from and also not leave out certain paragraph or sentences that he wrote.

    brothers/sisters interested on the full article can read it here

    since it's an 2004 article & we know by now that 50% daily water change is not the way to go thru NPS & tackle ammonia problem, so does buffering nitrite poisoning with only around 0.02% of salt (some seasoned hobbyist buffers at 0.3%, Abang David Soon at 0.1%) , new hobbyist should discuss what's being read to get latest info before applying it :)

  • ZackZack October 2012
    Posts: 232
    Hi Nocturnal,
    Thanks for highlighting. These are my reasons:
    1) Definitely the article is not mine & I post it not to claim any credit out of it. In Singapore context, I know the copyright act.
    2) I post on what I have read & remove the portion on writer experience on NPS as I do not want reader to have the impression that it sounds like I am the original writer. Admit my mistake for not saying upfront where the article is taken from.
    3) I post it here in the hope that those whom can spot where changes took place through time can bring up to the attention to other reader whom may have read the same article to take note of it.
    4) Others whom may have read similar article may only asked the portion of their interest here & rest whom read it especially newbies does not have the full story from head to toe.
    5) Think positively, the main idea on what I'm doing is share & hoping that there is an auditor whom can correct every single portion in the article that is no longer applicable.

    Hope this clear the air or wrong impression of me. Once again thanks for your highlighting & concerned
    My kois are my lover
  • ShukriShukri October 2012
    Posts: 4,881
    Quoting articles is all and good, but we need to be vigilant and careful as where the articles are gotten from. Sometimes, the author themselves are as newbies or are not that familiar with certain subject matters, which sometimes make them as equal level with many of us, as they themselves are just like us.......

    As a suggestion, when we post articles, best way is to ask questions and feedbacks from the Koi Community, what do the Koi Kichis think and it is in line with the common practices in this region etc........ That way many people can learn.

    Have a nice day Bro.......

    In Koianswers Forum, no one individual is above the rest. This is the Forum for the Koi Community.
    Post edited by Shukri at 2012-10-27 07:45:40 am
  • HDCuHDCu October 2012
    Posts: 1,117
    "Soft pond water should be avoided because it forces the koi to exert more effort in osmoregulation, the process of maintaining internal body water concentration to the correct level. Furthermore, a low KH results in pH instability, which can be lethal in extreme cases of pH swing. On the other hand, mineral deposits will form in the pond if the hardness exceeds 150 ppm. Note that some koi experts advise higher hardness levels than this (even up to 300 mg), if only to assist the fish in osmoregulation. "

    So what do Japanese breeders(koi experts) prefer , a ph of 7 or a ph of 8? soft or hard water?
  • harry_luhurharry_luhur October 2012
    Posts: 808
    @adik, you done your homework, AND i agree with wise word from Abang Shukri.

    PS. Adik :)

    Harry Luhur
    Post edited by harry_luhur at 2012-10-27 08:06:08 pm
  • niveknivek October 2012
    Posts: 1,251
    If there was a compilation of all GC winners' pond water parameters, we might be able to derive the best water to have. I am starting to see what works for certain koi types will not work for others..just a thought :)
    Post edited by nivek at 2012-10-27 08:13:39 pm

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