Test Kits

Colour comparison card for the Aquarium Pharmaceuticals pH test kit.

Introduction

Test kits are a method of a determining the value for various water parameters. Generally, it is unwise to take the values generated by a hobbyist-grade test kit as the absolutely correct value for what conditions the water sample is currently under. It is far better to use them as a guide, particularly for trends over time. Chasing the "perfect numbers" is a very bad idea and will typically cause more trouble than it is worth.

Also of concern, is what parameters to test. Generally, not everything is equally important, see What Parameters to Test for more information on this.

If an unusual reading is obtained or a new test kit is purchased, then it should be validated.

Types

There are basically two methods utilised in hobbyist kits: colour matching and titration.

Colour Matching

With colour matching, a measured sample of water is placed in a vial or similar (Seachem use wells), one or more reagents are added to the sample and the resulting colour of the sample is compared to a colour chart. This method is used for most test kits for most parameters. Accuracy is dependent on the lighting under which the comparison is made and is influenced by the judgment of the person doing the test.

An extension of the colour matching kits, is the use of a colorimeter which does the colour matching for you. Hach is the company that makes these:

• Water Testing Devices for Advanced and Professional Aquarists: The Hach 800 Series Colorimeters by Dana Riddle - Advanced Aquarist's Online Magazine

Titration

Titration kits are generally used for alkalinity, calcium and magnesium. A measured sample of water is added to a vial or well, one or more reagents are added to colour the sample and then a titrant is added slowly until the colour changes. The quantity of the titrant added determines the concentration. Titration tend to be far more accurate as they are not subject to human judgment of colour.

Gallery

• 
  Example of a colour matching chart, for the Salifert phosphate test kit
• 
  Example of a colour matching chart, for the Aquarium Pharmaceuticals nitrate test kit
• 
  Example of a titration test kit, for the LaMotte alkalinity test kit.
• 
  Example of a colour transition for a titration test kit, for the Salifert alkalinity test kit.

Brands

There are various brands of test kits available and some are more accurate or reliable than others. The popular choice in kits appears to be Salifert which are readily available at a good price, are generally reliable and are easy to use. That's not to say other brands are less reliable but simply that Salifert seems to be the most popular. A Search on the RTAW Forums will provide opinions.

• Aquarium Pharmaceuticals
• Aquarium Systems
• Aquasonic
• Hagen
• LaMotte
• Marine Enterprise
• RedSea
• Salifert
• Seachem
• TropicMarin

Instructions

The following brands have some of the instructions provided on the linked pages:

• Aquarium Pharmaceuticals
• LaMotte
• Marine Enterprise
• Salifert
• Seachem

Meters: Alternatives to Test Kits

If you don't like using test kits or want a more accurate way to determine water parameters, there are a number of meters available that can make life a bit easier. These can typically also be used with or in conjunction with an aquarium controller.

pH

pH meters are probably the most widely available meters and are made by a number of different companies. They are available in straight meters which can be used for single readings and others can be used as monitors which you can leave in the tank.

Calcium

Meters for measuring calcium have been around for years but they are very expensive pieces of equipment usually reserved for laboratories. American Marine have recently made a relatively inexpensive meter available which appears to be quite accurate. See: Electronic Calcium Monitoring.

Resources

• Electronic Calcium Monitoring by Randy Holmes-Farley - Reefkeeping Magazine
• Water Testing Devices for Advanced and Professional Aquarists: The Hach 800 Series Colorimeters by Dana Riddle - Advanced Aquarist's Online Magazine
• Hach’s 'Test Strips' for Ammonia, Nitrite, Nitrate, pH, Total Hardness, and the Digital Titrator by Dana Riddle - Advanced Aquarist's Online Magazine