Photometer, digital, Chlorine

Product Code: FCDP
An easy to use, portable, photometer that ensures accurate analysis of free, combined and total chlorine. Ideal for situations where higher levels of accuracy and consistency of measurement are required.

User notes
This equipment is ideal for water team leaders to enable them to verify the accuracy of results of technicians who are using the Pooltester kit or Test Strips.

Digital photometers use a different reagent tablet to the visual comparison test methods. The tablets required are non-effervescent as any bubbles in the sample will effect the accuracy of the reading. 

Components included
Palintest Chlorometer kit PTS 045D
Line# Quantity Unit Description
1 1 Each Compact Chlorometer
2 2 Each Sample cuvette with light sealing lid
3 1 Each Cuvette cleaning brush
4 4 Each Crush/stirring rods
5 1 Pack(s) Tablets, rapid test, DPD1, 50 pce: DPD3, 50 pce
6 1 Each Case, with belt loop
Consumables Oxfam Code: FP11
Line# Quantity Unit Part No. Description
7 2 Box(es) AP011 Tablets, photometer, DPD1, 250 pce

Note: The reagent tablets for a photometer are not the same as used for the visual comparator test kits

For additional reagents:
Parameter Range (mg/l) Palintest Code Oxfam Code
Chlorine - Free (DPD1) 0-5 AP011 FP11
Chlorine - Total (DPD3 use with DPD1) 0-5 AP031/1 FP31

Understanding the difference between free and combined chlorine is crucial to understanding water quality after chlorination. Testing the water for both free and combined chlorine allows you to know whether the water you've chlorinated is of sufficient quality to drink or disinfect, depending upon your application.

So, what's the difference?

Pure chlorine exists as a molecule as a gas (Cl2 ) and when dissolved in water it will react with water to form mostly hypochlorous acid (HOCl):

Cl+ H2O ↔ HCl + HOCl

Depending on the pH of the water (see image below), the hypochlorous acid (HOCl) will partially dissociate to the hypochlorite ion (OCl-). Both hypochlorous acid and hypochlorite disinfect water but hypochlorous acid is a more effective disinfectant.


By definition, free chlorine refers to all chlorine present in the water as Cl2(gas), HOCl(aqueous solution) and OCl-(aqueous solution).

Portable water testing methods such as DPD do not distinguish between these three species, and they are all termed free chlorine, with the capability to disinfect micro-organisms in the same way as Cl2. Free chlorine will often be denoted as Cl2 in water treatment applications and literature, but can refer to any of the three forms.

When free chlorine is initially added to water it can undergo a very quick reaction with other contaminants in the water, mostly ammonia, NH3. This will result in the formation of chloramines, and the 'free' chlorine is converted to 'combined' chlorine:

NH→ NH2Cl → NHCl→ NCl3

That is; ammonia → monochloramine → dichloramine → nitrogen trichloride (trichloramine)

  • Ready To Ship: 2 days
  • Made In: United Kingdom
  • Packaging: Carton
  • Item Dimensions (cm): 20 x 15 x 11
  • Volume (m³): 0.003
  • Weight (kg): 1