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/Aquatic Gardens, Design, Construction & Maintenance

Test Kits & Testing for Ponds


By Bob Fenner

Aquatic Gardens

Ponds, Streams, Waterfalls & Fountains:
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples

V. 1 Print and eBook on Amazon
V. 2 Print and eBook on Amazon

by Robert (Bob) Fenner

How the dickens are you going to be able to determine what your water quality is? By using the tools listed here, sheesh!

Water garden testing is really a simple, cook-book, follow the steps affair. There are inexpensive measuring devices and assays, and super high tech. electronic digital meters and dosers. I'll assume you don't want to convert a room to look like a nuclear power plant control station, and cover the basic tests for the parameters we discussed in the last Section.

Routine water testing need not become a full-time commitment; instead look onto such "windows" as an opportunity to keep track of and avoid noxious chemical conditions.


"Average kinetic energy", aka temperature is handily measured with an alcohol or mercury thermometer that reads over the range of your weather. There are "pond" and swimming pool thermometers you can buy that have a plastic housing to protect against breakage; this is a good idea.

Alkalinity/Acidity and pH:

These tests come in nifty kits together or apart, alkalinity/acidity and pH are most often determined through what's called a colorimetric assay. Don't be thrown or snowed by any of this fancy terminology; for liquid chemical types all that you do is 1) scoop up a water sample in the provided test chamber, 2) in turn place a number of drops of solution(s) 3) cap (not with your finger) and mix, 4) compare resultant color with a standard.

Alternative to liquids are the ever-so-handy "strip" tests that incorporate a sample "stick" with chemical reagent "pads" that you dip into the test water, wait a while and compare once again, with provided color scales. What could be easier?

There are other tools, "pens" and electronic meters, titration end-point, spectrophotometry... their added expense with little more accuracy is not warranted.

Measuring the Nitrogen Cycle:

Ammonia, nitrite and nitrates as detailed in last Section, are great as a rough and tumble gauge of metabolite (waste, nutrient) build-up and cycling in your system. The first two tests you'll probably only need to do when first breaking in the aquatic feature, and should you encounter trouble that results in disruption of your bacteria populations. I encourage you to pick up the more reliable and less toxic alkaline-cyanurate (salicylate) versus Nessler's-type test kit for ammonia. Which type you're looking at will be printed on the packaging.

Tests for ammonia, nitrite and nitrate are color-comparison types as per ph above. The better kits have the comparative standards cast in plastic versus printed on paper; the very best incorporate a neat "empty" test chamber that goes behind the standards that compensates for dissolved color in the water sample. Please see notes below re storing and discarding these test mixes.

Bio- Algicide Treatment Chemicals:

Of the many treatment chemicals available for keeping fountains, bird baths et al. sterile, I'll just elaborate on the two most appropriate chlorine/bromine and copper. I encourage you to think long and hard before utilizing other "economic poisons"; most are harmful to surrounding landscape and may pose hazards to visiting animals.

Chlorine/Bromine and Conditioner

Of the two most-readily available test kit types, OTO and DPD, the heavy favorite is the latter. Ortho-tolidine solutions are just too toxic for use, and the DPD tablets are far more easy to handle. A reagent "pill" is peeled from it's wrapper, dropped into the test chamber which is covered by a provided cap, the solution mixed and compared with a color standard for concentration.

Pre-treated pads on strips can be had as per those described for pH. Be aware of the difference in using any of the liquid or dry types of tests for chlorine or bromine that there are two measures, "free" and "total". Free refers to the amount of sanitizer in the active state, whereas "total" includes all biocide in active and reserve formulation. Most commonly, the difference between free/total is assessed by allowing a brief period of time to pass between readings.

A good free sanitizer level to maintain is 1-2 ppm, more than 10 ppm may result in damage to metal or alkaline elements in your system.

Conditioner (cyanuric acid) is either measured mathematically and applied all at once when total water changes are executed or by way of a test kit. The standard conditioner kit works a little different than those described so far; a water sample has so many specified drops of a reactant applied to a test chamber and a rod with a dark dot is raised and lowered till the dot is just barely visible. The reading at the calibrated side of the test chamber will give you your reading. A conditioner level of 50-100 ppm is ideal; too much and you may have to drain and replace part of the water to avoid "chlorine (or bromine) lock", a situation in which the percentage of free chlorine is too low. Too little or no conditioner and you will find that you'll have to add sanitizer very frequently.


We'll go over extensively in Sections E) ii) b) and 1). Testing for free and bound copper ion is a matter of colorimetrics as per pH.

Sources of Test Gear:

For poisoned systems utilizing chlorine/bromine and conditioner, chemicals and test gear may be purchased at a swimming pool or spa retail outlet. If you have a living-system, make sure and keep the cleaning tools, nets, hoses, etc. separated from that used for the pool/spa as the residual chemicals are unhealthful for your livestock.

Living system test equipment may be purchased from aquatic garden retail and mail order businesses, pet-fish outlets, or chemical supply houses. Be aware that there are many grades, from the simpler tropical fish hobbyist variety (e.g. Tetra, Aquarium Pharmaceuticals), on up (e.g. Hach, LaMotte)... with some attractive multiple-parameter options. Do compare such features as the number of tests, colorimetric standards format, sturdiness of casing, and ease of replacing reagents in your buying decisions.

Storage and Discarding:

Rather than a whole separate article devoted to chemical safety, please read and heed the following "tips".

1) Use chemicals and test kits for them only specified for their specific use.

2) Discard of all treated water and test mixes down the sanitary sewer, not on the landscape or "sweet-water" storm drain system.

3) As per two above, take care to keep treatment and test chemicals off your skin and rinse your gear and hands after use.

4) Store test and treatment chemicals in sealed containers in a cool dry place out of the reach of children and animals.

5) Add the treatment chemicals to the water not the other way around; and never mix treatment chemicals together.

6) Be a safe and conscientious consumer and follow the instructions provided on the treatment chemicals. Save the precaution and danger inserts with the containers for reference.

7) By all means record the treatments, test results and your observations in your system log.

Dated Reagents:

Dear Reader, my "fifteen minutes of fame" was spent on The People's Court" show defending one of our retail outlets (Wet Pets) against the claims of a plaintiff pair that claimed they had gotten a "false negative" test from an old test-kit we had sold them. Judge Wopner saw things their way after conferring with some Los Angeles pet outlets, determining that the reagents in the kit were way past their useful lifetime.

Don't let this happen to you. The hobby kits are accurate and precise enough for our use, but the pillows, powders, strips and liquids are only good for so long. Be aware of this and keep your eye on their shelf life. You should find product inception dates printed on the reagent pillows or the accompanying box literature.


One last mention of the need for patience and understanding in taking and reacting to measurements of water quality. Please don't get in over your head with equipment and tests without concomitant awareness of what they're results mean.

By all means do the tests valuable to you and your set-up; and keep a record in your logbook. A brief review of data points can grant you an expansive view and warning of impending problems. A few dollars and minutes spent on testing will save you much time and money in maintenance and lost livestock.

Bibliography/Further Reading:

Kuhns, John Farrell. 1990. Aquarium and pond water testing; the only way to determine the quality of the water is to test it. AFM 10/90.

Meyer, Stephen M. 1989. The pond in springtime; as Winter turns to Spring, special precautions are necessary to maintain the health of pond fish. AFM 4/89.

Aquatic Gardens

Ponds, Streams, Waterfalls & Fountains:
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples

V. 1 Print and eBook on Amazon
V. 2 Print and eBook on Amazon

by Robert (Bob) Fenner
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