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Bill OTMS
06-11-2007, 11:40 AM
Basic Water Quality Limits

Water Quality: What is it?
Itís a funny thing. When dealing with sick fish you'll often hear someone say "maintain excellent water quality" as part of the treatment. Likewise, you'll hear "my water quality is perfect". But what exactly are the acceptable limits of each water quality parameter?

pH:
Generally speaking, koi will thrive in water which is maintained at a pH between 6.8 and 8.6. If you are accustomed to maintaining fussy tropicals, this huge of a pH range may seem counter-intuitive... but its real. Koi will quickly adapt to whatever reasonable pH you throw at them. More important than the actual pH value is the stability of the pH. A day-to-night and day-to-day variation of 0.3 pH points should be considered the maximum allowable. Common wisdom has it that a significant pH fluctuation from morning to evening is "normal" and "healthy". This is not true. A significant fluctuation is generally indicative of sagging carbonate levels, insufficient aeration, or an unhealthy fish load.
For an in-depth discussion of pH see pH.

Carbonate Hardness or Total Alkalinity (KH)
Also called "buffering capacity", this water parameter is overlooked by better than 90% of koi hobbyists. The measurement of the carbonate levels provides a direct indication as to the buffering characteristics of your pond water. Generally speaking and within reason, more KH is better. Koi will tolerate a very wide range of KH, but they tend to suffer from pH-induced stresses as the KH drops below 40 ppm. KH is optimally kept between 80 to 120 ppm, but again, koi are hearty animals and will tolerate very high KH's (up to 300 ppm) with no ill effects. Any KH measured below 40 ppm demands attention, for a pH crash is lurking in your immediate future.
For an in-depth discussion of KH see Carbonate Hardness.

General Hardness (GH)
General Hardness is a measurement of dissolved minerals, principally calcium and manganese. Unlike KH, GH has no significant buffering effect. Koi appreciate a GH-rich water from which they are able to assimilate calcium for strong bones. Especially in the case of fast-growing fry, ample calcium should be provided. Generally speaking, koi will suffer if the GH is less than 80 ppm.
For an in-depth discussion of GH see General Hardness (GH)

Ammonia
Ammonia is a highly toxic compound produced by fish as a result of their digestion of protein. Any detectable ammonia in an established pond is cause for immediate concern. To be sure, more fish are killed by ammonia than from all other factors combined. The maximum allowable ammonia reading is zero.

In a new or uncycled pond, ammonia will be present in significant quantity until the biofilter populates with sufficient quantities of nitrifying bacteria. The amount of ammonia which can be tolerated is dependent on several factors:
1. The pH: Higher pH's cause a greater percentage of ammonia to exist in the toxic, un-ionized form. This is not to suggest that dropping a ponds pH in response to an elevated ammonia level should be tried. Indeed, fish which are already ammonia-stressed will not generally tolerate a significant pH change.
2. Temperature: Higher temperatures increase the effects of ammonia toxicity. Elevated temps also reduce the oxygen level while simultaneously increasing the output of the fishís metabolic wastes.
3. Oxygen Level: Maintaining oxygen levels at the saturation point tends to somewhat offset the effects of ammonia. Low oxygen levels combined with ammonia at any level will kill fish in droves.
4. General Health Of The Fish: Strong, healthy fish can tolerate a significantly elevated ammonia level for a short time. Fish which are weak, stressed, or carry a considerable burden of pathogens (flukes, etc) will tolerate ammonia poorly if at all.
For an in-depth discussion of ammonia see Ammonia (NH4).

Nitrite
Nitrite is the intermediate step in the bioconversion process. Ammonia is converted into nitrite before being again converted into nitrate. Nitrite, like ammonia, is highly toxic to fish. Like ammonia, the only acceptable number is zero.
For an in-depth discussion of nitrite see Nitrite (NO2).

Nitrate
Nitrate is the final product of the bioconversion process. Once thought to be harmless to fish, new studies are showing that nitrate may be considerably more toxic than originally thought. The maximum recommended nitrate level is 40 ppm where adult fish are kept and 10 ppm where fingerlings are present. There is no minimum level although zero would be desirable in the absence of plants.
For an in-depth discussion of nitrate see Nitrate (NO3).

Temperature:
Tough little campers they are, koi will tolerate temperatures from 33F to over 90F if the change occurs slowly and sufficient oxygen is provided. For best growth, water temperatures should be maintained between 68F and 78F. At these temperatures, koi will display excellent appetite and immune function. A steady temperature is more important than any absolute temperature. Koi routinely exposed to temperature fluxuations of more than 7F per day may become prone to various ills and show signs of stress. There is considerable evidence which suggests even a 3F change per day can interfere with best growth and color.
For an in-depth discussion of temperature see Temperature.

Oxygen
Dissolved oxygen levels in excess of 6 ppm are needed to successfully keep koi. Below 6 ppm, there is little room for error and any stress or disease may result in mortality. Having said this however, it is interesting to note that healthy koi can tolerate 3ppm O2 for short periods. Because it is very difficult to over-oxygenate a pond, most ponders attempt to keep the oxygen level at the saturation point. Generally speaking, itís very difficult to over-saturate a pond.

Carbon Dioxide
Carbon dioxide (CO2) is a byproduct of normal fish respiration and is also produced by plants at night when photosynthesis has stopped. Koi need water relatively free from CO2 for best growth, health and color. In a perfect world, CO2 levels would essentially be zero but the effects of plants, carbonates, pH and aeration factors all contribute to a measurable CO2 level. For koi, CO2 levels must be maintained less than 5 ppm with values less than 2 ppm being ideal. Above 10 ppm, lethargy and loss of appetite will occur. By 50 ppm, the fish enters a stuporous state and cannot respond to most external stimuli. Most ponds (especially those which are heavily planted) tend to exceed 5 ppm at night.
For an in-depth discussion of carbon dioxide see Carbon Dioxide (CO2) as well as the graph showing the relationship of CO2 levels to KH and pH.

Copyright © 2000 by Roark. All Rights Reserved.
Email comments to: roark7@aol.com
Page rev 8.12 of 15DEC98

cindy
06-19-2007, 01:05 PM
very nice. PH (power of hydrogen)

cindy
06-19-2007, 01:07 PM
from ER:One further note: If you have a bead filter in your filtration system, the Kh must be kept at 200 ppm or more for it to function properly.

Baking soda: 2 to 3lbs per 1000 gallons will raise and stabilize Kh levels and keep the Ph at 8.3 to 8.4. Raise your Ph/Kh slowly over several days. Use maintenance doses of baking soda to keep them at a desired level.

SDGeorge
08-27-2007, 06:37 PM
from ER:One further note: If you have a bead filter in your filtration system, the Kh must be kept at 200 ppm or more for it to function properly.

Baking soda: 2 to 3lbs per 1000 gallons will raise and stabilize Kh levels and keep the Ph at 8.3 to 8.4. Raise your Ph/Kh slowly over several days. Use maintenance doses of baking soda to keep them at a desired level.

Exerpt from Roddy Conrad: A pound of baking soda added per 1000 USA gallons increases the alkalinity by 71 ppm.

:confused:

efurman
01-04-2009, 11:14 AM
Have an outdoor 1000 gal gunite(concrete) pond(two months old. Have "cured it" by bringing the PH down to 5(w/o fish) but the PH keeps rising over 3-4 days to 9. My fish source is my 1/3 acre mud pond which has a steady PH of 6.5. Test fish have not done well obviously.What to do??

CHICHI
01-04-2009, 12:05 PM
Have an outdoor 1000 gal gunite(concrete) pond(two months old. Have "cured it" by bringing the PH down to 5(w/o fish) but the PH keeps rising over 3-4 days to 9. My fish source is my 1/3 acre mud pond which has a steady PH of 6.5. Test fish have not done well obviously.What to do??

Some info :yes:


First off, let's explode some myths. There is one bit of advice that many casual water gardeners persist in passing on to novices, and it lets the novices in for headaches they would not ordinarily have. Build the pond, the self-appointed experts advise, fill it, plant it, sit back, and wait. They go on to say that everyone knows water-lilies won't grow well in a brand new pond, but a "natural mellowing" takes place after the first season, and the lilies will then begin to reach out a bit. After the flowers have become well established, goldfish, too, will find the pond livable.
One of the difficult things about beating down this misinformation is that it is partially true. Fill an uncured pond and plant it with strong-growing water-lilies and, sure enough, they'll grow. They won't grow well. Probably they won't even bloom. But they will grow. Also it is true that after the first season, if the pond is well situated in the sunlight, the lilies will begin to bloom.
But this so-called natural mellowing procedure is merely attrition on the part of Mother Nature. In a year of rainfall, and subsequent run-off through the pond's drainage system, the entire water capacity of the pond is replaced many times, resulting at last in a fill that is no longer alkaline.
So I can't say that the natural mellowing story is an out-and-out misrepresentation. I can say only that it is a very slow and disappointing way of doing business. Why put up with a green pond for a whole, wasted season when you can cure it quickly, plant it, and within a few weeks see growth in your pond that is really worth watching!
A WORKABLE NATURAL CURE
Perhaps a great many water gardeners have confused so-called natural mellowing with a procedure we used to recommend to our customers. We told them to build their ponds in the fall, finishing them up at a time when the pond couldn't be planted for several months. The natural washing action of rain, sleet, and snow through the winter did a fine job of seaming the free lime off the surfaces of the new concrete. This is still good, efficient practice if the time element happens to fit in with your own construction plans.
If you cure the pond in this way, I suggest you help nature a bit and fill and empty the pond a couple of times during the winter-early and late in the season, when there is no danger of freezing-letting the water stay in the pond two to three weeks each time. As a final test, fill the pond and dip a piece of pink litmus paper in the water. The litmus will turn blue if appreciable alkalinity remains in the water. In this unlikely event, fill and empty the pond a few more times.

http://www.buildagardenpond.com/build/curinggardenpond.html
http://www.concrete.org.uk/fingertips_nuggets.asp?cmd=display&id=809
http://koiclubsandiego.org/library/alkalinity.php

As it is a small body of Water - you could keep "Flushing" it until the PH stabilises closer to that of your Mud Pond ..

RichToyBox
01-04-2009, 10:00 PM
Have an outdoor 1000 gal gunite(concrete) pond(two months old. Have "cured it" by bringing the PH down to 5(w/o fish) but the PH keeps rising over 3-4 days to 9. My fish source is my 1/3 acre mud pond which has a steady PH of 6.5. Test fish have not done well obviously.What to do??

What type of curing was done to the concrete pond? Concrete improves with age, providing it has access to moisture and temperature. The hydration process of converting the cement grains to a calcium-silicate hydrate gel, that provides the strength and watertightness of the concrete, has two byproducts. One is heat, and mass concrete will get very hot, while thinner sections may need supplemental heat in cold weather to continue hydration. The other is calcium hydroxide. The calcium hydroxide is drawn to the surface in the pore water within the concrete. Once at the surface it will mix with the pond water and raise the pH significantly, having a pH of around 13. If the concrete is allowed to surface dry for a couple weeks after a good month of moist curing, the calcium hydroxide that comes to the surface reacts with carbon dioxide in the air creating calcium carbonate in the surface pores. This densifies the concrete significantly, making it very difficult for the pond water to migrate into the concrete, and the drying of the surface allowed air to enter the pores. These air bubbles separate the pore water with a high calcium hydroxide content from the pond water inhibiting the transfer of the hydroxides to the pond.

At 2 months of age, I would suspect the pond has not had the opportunity to air dry. Keeping it filled with water, it will eventually cure to become more watertight, and dilute the hydroxides by wicking them out of the concrete. The use of acid for acid washing before filling will remove a lot of the calcium carbonate opening the pores, creating more interface with the hydroxides, lengthening the time needed to stabilize the pH rather than reducing it.

Adding baking soda will reduce the pH to about 8.3 provided their is sufficient calcium present, which should always be the case in a concrete pond.

If your tap water has any alkalinity, it is going to tend to have a pH much higher than the mud pond, whether it is in a concrete pond or not.

CHICHI
01-04-2009, 10:32 PM
What type of curing was done to the concrete pond? Concrete improves with age, providing it has access to moisture and temperature. The hydration process of converting the cement grains to a calcium-silicate hydrate gel, that provides the strength and watertightness of the concrete, has two byproducts. One is heat, and mass concrete will get very hot, while thinner sections may need supplemental heat in cold weather to continue hydration. The other is calcium hydroxide. The calcium hydroxide is drawn to the surface in the pore water within the concrete. Once at the surface it will mix with the pond water and raise the pH significantly, having a pH of around 13. If the concrete is allowed to surface dry for a couple weeks after a good month of moist curing, the calcium hydroxide that comes to the surface reacts with carbon dioxide in the air creating calcium carbonate in the surface pores. This densifies the concrete significantly, making it very difficult for the pond water to migrate into the concrete, and the drying of the surface allowed air to enter the pores. These air bubbles separate the pore water with a high calcium hydroxide content from the pond water inhibiting the transfer of the hydroxides to the pond.

At 2 months of age, I would suspect the pond has not had the opportunity to air dry. Keeping it filled with water, it will eventually cure to become more watertight, and dilute the hydroxides by wicking them out of the concrete. The use of acid for acid washing before filling will remove a lot of the calcium carbonate opening the pores, creating more interface with the hydroxides, lengthening the time needed to stabilize the pH rather than reducing it.

Adding baking soda will reduce the pH to about 8.3 provided their is sufficient calcium present, which should always be the case in a concrete pond.

if your tap water has any alkalinity, it is going to tend to have a pH much higher than the mud pond, whether it is in a concrete pond or not.

But not a PH of 9-10



efurman PH surges Have an outdoor 1000 gal gunite(concrete) pond(two months old. Have "cured it" by bringing the PH down to 5(w/o fish) but the PH keeps rising over 3-4 days to 9. My fish source is my 1/3 acre mud pond which has a steady PH of 6.5. Test fish have not done well obviously.What to do??

Flushing several times will help significantly - in the interim :yes: