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Water Quality Analysis
  The measurement of dissolved oxygen, DO, is essential to monitor and maintain the health of the aquatic environment. Low DO can result in poor appetite, growth and poor health of fish. The measurement of DO is important in the use and monitoring of management tools, such as aeration devices. In fisheries, low DO results in poor catches, and therefore angler revenue. The detection of low DO can warn of impending, preventable problems, such as the collapse of algal blooms, or proliferation of zooplankton.
    Dissolved Oxygen Meter and Probe
An inexpensive way to measure DO. This long-established methodology (the Winkler Method) involves the mixing of reagents with the water sample, gives accurate and reliable results, and can be done in the field.
Ammonia, Nitrite, Nitrate
Ammonia is an important waste product of fish, and a by-product of some decomposition processes. Its importance relates to its toxicity to fish, and other aquatic organisms. In aqueous solution, it is present in balance in 2 forms; ionised ammonium (NH4+) and the unionised ammonia, NH3. The latter is much more toxic to fish than ionised ammonium. The balance between the 2 forms is affected by pH and temperature. Consequently, there is little point in measuring ammonia alone, without measuring pH.
As a toxic waste product of fish, it must be removed from recycling, holding systems. This is done using biological filtration, where a suitable environment is provided for the colonisation of purifying microbes (see Nitrifying Bacteria). These breakdown ammonia into nitrite (also toxic) which in turn is broken down by different microbes into relatively harmless nitrate.
All 3 compounds are aquatic nutrients, and support aquatic algae (green-water and blanket weed) and water weeds. Man's activities, through agriculture and sewage disposal, often enrich water bodies with these nitrogenous compounds.
Colorimeters take the operator-error out the measurement of the colour results of sample testing.
Individual colorimeters are available for all of the above parameters. However, we can offer a very economic way to measure most of the parameters important to the fish environment; the C103.
ammonia, high and low range
copper, high and low range
nitrite, high and low range
dissolved oxygen
phosphate, high and low range
Let us know your requirements, and we can give further guidance and a quotation Contact us
  Where the water sample is clear, a colorimeter is an inexpensive way to measure DO. Reagents are added to the water sample, and the resulting colour is measured by the instrument. This removes the need for the subjective assessment of colour comparisons.

Dissolved Oxygen Test Kits
The monitoring of ammonia, nitrite and nitrate is therefore important in aquaculture, fishery management and fish holding.
We can offer a broad range of instruments for the measurement of pH, ranging from spot-checkers, to inexpensive, continuous monitors
chlorine, free and total
The C103 is a new bench-top, multi-parameter colorimeter that can be used to measure all of the following:
         Dissolved Oxygen Colorimeter

 By monitoring the DO level, it is possible to keep your fish feeding AND ALIVE !  
It is possible to answer questions such as:
"Do I need supplementary aeration ?"
"When do I need to start using my aerators?"
"Do I need to use my aerators all of the time ?" 


Hanna Oxygen Meter

HI 9147


Oxyguard Products

A range of equipment for the measuring, monitoring, alarm, control and data logging of dissolved oxygen.  There is a very wide range of equipment available, some of which is described here. 

All of the equipment has in common:


ease of use

high reliability

low maintenance

value for money

Hand Held Meters

The easiest way to measure dissolved oxygen

The Oxyguard Handy Series

The new concept in pocket meters!
  OxyGuard Handy Polaris

This range of meters and probes have been designed to be highly accurate, yet practical for use in typical field applications such as AQUACULTURE, FISHERY MANAGEMENT and the WATER INDUSTRY.

Key Benefits:

easy to use -

Special, no-warm-up  probe means it is always ready for measurement
Round design fits comfortably in the hand
Flat foil push buttons, easy-wipe
Illuminated display*
Clip for convenient belt- or clip board-fixing

completely sealed - it floats, if dropped in the water!  - flat foil seals the the front, O-ring seals the rear cover

case machined from a solid block of POM plastic
* not Alpha


Polaris, O2 as ppm (mg/l) and % saturation, temperature and  illuminated display
Gamma as polaris, plus salinity compensation 
Delta as Gamma, plus data logging,  barometric pressure compensation, time and date

Technical Advantages

No microprocessor programs to run through - just press the button and measure !
Fits comfortably in the hand with no protruding knobs.  Flat-foil, easy to use. wipe-clean push buttons
Waterproof.  Can be used in any kind of weather.  Submersible, and even floats, if dropped in the water !
Galvanic type probe with no warm up time - always ready for use !
Fully temperature compensated - no dials to set
Very quick response time
Probe is stored dry, therefore easy to obtain quick and reliable calibration
Excellent long term stability - one daily calibration check sufficient
Tough probe membrane - can be wiped clean with a cloth or paper
Probe does not need regular service or renovation
Runs for more than 1000 hours on standard 9v battery
Illuminated display (Beta, Gamma, Delta)
Special highly flexible cable

Probe type Galvanic cell, self-polarising, self temperature compensating
Cable length Standard 3m.  Any length available on request
Operating conditions Probe: -5 to + 50°C, meter -20 to 50°C
Measuring range Standard: 0-50.0 ppm (mg/l) and 0-600% saturation.  Will indicate up to 199.9ppm (mg/l) and 1999% saturation
Accuracy: Measurement accuracy depends on calibration accuracy.  Typically better than +/- 1% of measured value +/- 1 digit within the standard measuring range
Repeatability Typically better than +/- 0.5% of measured value
Response time 90% of end value in less than 10 seconds
Accuracy, temperature +/- 0.2°C (Beta,  Gamma and Delta)
Salinity Compensation 0-50 ppt salinity.  Set using push buttons (Gamma, Delta only)
Dimensions 96mm diameter x 36mm + belt clip (if used) 
Standard accessories Spare membrane cap, membranes, electrolyte and storage bag
Data logging (Delta only) Manual (event) or automatic (time interval, from 2 to 60 minute intervals) 


New Hanna HI98128, waterproof meter


 Oxygen Monitoring                  

under construction
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Office: Spirex Aquatec Ltd, Bradley Green, Redditch, B96 6TN, Registered in England and Wales. VAT Number GB803548439.
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Office: Spirex Aquatec Ltd Bradley Green Redditch B96 6TN