
Hanna Instruments-3831F Chlorine (Free) test kit
Colorimetric testing is a method of determining the concentration of a chemical element or compound (organic or inorganic) in a solution with the aid of a colour reagent.
Our test kits measure the strength or weakness of a chemical presence according to the degree of colour saturation. Ie – if it is pale in colour, then the chemical concentration is low. If the colour is strong, then the chemical concentration is high. Simply add the reagent to the compound to be tested and match the colour gained against a colour chart included in the kit.
Free Chlorine test kit
The Hanna Instruments-3831F free chlorine test kit is equipped with all you need to determine free chlorine levels in water. Free Chlorine reacts with ammonium ions and organic compounds to form chlorine compounds resulting in diminished disinfecting capabilities compared with free chlorine. These chlorine compounds together with chloramines form combined chlorine. Combined chlorine and excess free chlorine together result in total chlorine.
While free Chlorine has a much higher disinfectant potential, combined chlorine has a much higher stability and has a lesser volatility. There should be sufficient levels of unreacted free Chlorine for adequate disinfection, but not so much as to become harmful.
Order information
The Hanna Instruments-3831F free chlorine test kit comes supplied with; colour comparison cube, 20mL reagent 1 and 15mL reagent 2.
Check out our Checker® HC Handheld Colorimeters – a highly-accurate and affordable way to test for chemicals using a gadget that sits perfectly in the palm of your hand and also fits nicely into your pocket.

Frequently Asked Questions
Clear answers to help you choose the right water testing solution with confidence
Which brands of water testing kits do you supply?
    
  
  
Do you provide kits for both home and professional use?
    
  
  Yes — whether you’re a pool or spa owner, aquarium keeper, utility company, or a university laboratory, we have the right solution for your needs.
Can I arrange servicing or calibration for my photometer?
    
  
  Absolutely. We also provide servicing and calibration to keep your photometers accurate and reliable.
How quickly do you dispatch orders?
    
  
  Orders placed before 2:30 pm (Monday–Friday) are dispatched the same day. We also ship on Saturdays for your convenience.
Which couriers do you use for delivery?
    
  
  We deliver through UPS, DPD, and Royal Mail. You can also choose to upgrade to next-day delivery at checkout.
What is your return policy?
    
  
  We accept returns within 14 days of delivery provided the items are unused, in their original packaging, and in resalable condition. Please contact our team before returning any items.
Can I place bulk or business orders?
    
  
  Yes, we welcome bulk, trade, and institutional orders. For tailored pricing or large quantities, please get in touch with us directly.
How can I get help if I’m unsure which kit to buy?
    
  
  You can call us at 📞 +44 (0)115888 2726 and our team will guide you in choosing the most suitable kit for your needs.
