








Hanna Instruments-77400P pH Combination Buffer Solution Kit 4.01 & 7.01 5 x 5 20ml sachets
Achieve accurate pH readings and check your meter and electrode is functioning correctly with Hanna buffer solutions. Available in convenient, ready-made pH values, Hanna has a certified value calibration solution with an accuracy of +/- 0.01pH @ 25◦C for all requirements.
Available in 230ml, 500ml, 1 litre, and 1 gallon bottles, plus individually sealed foil sachets containing 20ml of ready-to-use solution.
*For even greater accuracy, scroll down to read Hanna’s Technical and Millesimal Buffer range explained.
Hanna Instruments-77400P combination pH buffer kit with 5 x 20ml sachets of pH 4.01 and 5 x 20ml sachets of pH 7.01
The pH 4.01 & 7.01 buffer solutions in quick and easy to use 20ml sachets are the most popular buffers used before analysing samples. Ideal for those requiring an accurate acid or neutral reading, particularly suitable for those working in water purification plants, the food industry, aquatics, and Hydroponics, and in any environments where the pH is expected to be acid or neutral.
The single dose sachets are really handy with each sealed sachet holding just the right amount of solution. Each time a meter or electrode is calibrated using the Hanna sachets, it is like using a newly opened bottle of solution!
Benefits of individual packaging
- Ideal for users who do not calibrate frequently
- Ideal for field use due to portability
- Every sachet is as fresh as the day it was packaged
- Light block packaging prevents oxidation from UV light that could alter the buffer value.
Buffer solutions should be stored at 25°C, away from direct sunlight for accurate readings.
To correctly maintain your meter/electrode, we highly recommend use of a Hanna cleaning solution, as well as a buffer, for maximum performance every time. pH4, along with pH7, can also be used as an emergency storage solution.
Hanna buffer solutions are prepared, ready-to-use, according to precise formulas and standardised in accordance with the National Institute of Standards and Technology (NIST) to ensure quality and accuracy. All solutions show a batch number, an expiry date, and the correlation table between pH and temperature. A certificate of analysis is available on request. All bottled solutions are sealed with an air tight, tamper-proof seal to prevent any Carbon Dioxide from entering and causing a change in the pH buffer value.
Remember:
- Calibration only counts when using fresh solutions and properly cleaned electrodes every time.
- Routine maintenance will ensure accurate readings while extending the life of the electrode.
Useful information:
Colour Coding for 1L and 1 gallon bottles:
pH 4.01 - Red
pH 7.01 - Green
pH 10.01 – Violet
All calibration buffers are made to a premium quality, produced in accordance with ISO 3696/BS3978 standards using high purity salts, deionised water, certified weight-checked balances, and Class A glassware in a temperature controlled environment monitored with certified thermometers.
All bottles meet with FDA Standards (US Food and Drug Administration).
Specifications
pH Value@25°C : 4.01 & 7.01
Size: 20 mL
Package: 10 sachets (5 each)
Certificate of Analysis: No

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.