Water Testing

Optimum water conditions must be maintained at all times to minimise stress. Crowding, dissolved oxygen depletion, rapid changes in temperature, incorrect feeding and osmotic imbalance are all well known causes of stress and must be avoided. Sub-optimum conditions, while not immediately lethal, may stress the fish, resulting in delayed mortality or failure to grow. Everyone involved in fishkeeping should invest in water quality test kits. An excellent water quality management program will result in fewer fish disease problems, better growth and less use of chemical treatments. The cost of test kits will pay for themselves many times over; both in numbers of fish saved and increased enjoyment of the hobby. For aquarium keeping, the high precision of sophisticated analytical methods is not needed to make informed management decisions.

Intensive stocking in recirculating systems and aquariums requires frequent monitoring. If fish are maintained at high densities, then temperature, dissolved oxygen, ammonia, nitrite, and pH should be monitored regularly. At lower stocking densities, water quality parameters can be monitored less frequently. However, regardless of the frequency, monitoring should be conducted at a standard time of the day. The time of measurement and observed values should be recorded, as good record keeping is essential for successful fishkeeping.

Alkalinity and hardness can be measured less frequently, perhaps once a week, as they do not fluctuate as rapidly. Carbon dioxide should be monitored closely and the means to correct problems should be readily available. It is preferable to monitor dissolved oxygen early in the morning, when conditions stressful to fish are most likely to occur. Conversely, temperature and pH in ponds are best measured during the late afternoon. Chlorine or Chloramine levels in tap water should be determined so that corrective measures can be initiated.

Numerous test kits are available on the market from which you can choose, but they can vary in quality and price. You are therefore advised to select test kits carefully and not buy the first one you see on the shelf. Outdated reagents are a major source of inaccurate tests resulting from kits that have a limited shelf life. If used beyond their shelf life, then they will not give accurate, reliable results.

Some manufacturers print use-by dates on their kits but unfortunately, these manufacturers are in a minority. If you have a test kit without a use-by date, and you have had it for over six months, then you should replace the test chemicals. Test kits containing dry reagents are usually superior to kits that contain liquid reagents. Liquid reagents are generally less expensive but over time become unstable. Reagents in a dry form generally remain stable for longer periods. The most stable way of storing dry reagents is in sealed foil pouches; this protects them from oxygen, moisture, and light until they are used. Several aquarium test kit manufacturers have adopted this type of packaging.

© Copyright Adrian R. Tappin
Updated December, 2000.