Hanna Instruments HI-735 Total Hardness Low Range Checker Handheld Colorimeter
A great all-rounder. The HI-735 is designed to determine total hardness (as CaCO3) in drinking and process water, heating and cooling systems, swimming pools and spas. Also suitable to be used in agriculture, food and beverage industries.
This handy Checker is easier to use and more accurate than chemical tests kits. It is dedicated to a single parameter. It has single button operation system and easy to use.
The large LCD is easy to read and the auto shut-off feature assures the battery will not be drained.
It may be small, but it is certainly a big convenience!
Ideal for:
- Drinking water
- Process water
- Heating and cooling systems
- Swimming pools, hot tubs and spas
- Agriculture
- Food and Beverage industries
| Water Hardness Guide | ||
| Hardness classification | Parts per million (ppm) | Grains per gallon (gpg)* |
| Very soft | <17.1 | <1.0 |
| Soft | 17.1 to 60 | 1 to 3.5 |
| Moderately hard | 61 to 120 | 3.5 to 7.0 |
| Hard | 120 to 180 | 7.0 to 10.5 |
| Very hard | 180 + | 10.5 + |
| * 1 grain per gallon = 17.1 ppm |
Safety Data Sheets
When using any form of chemical, such as Hanna reagents, it is important you download the relevant safety data sheet and make yourself aware of any precautions you should take when handling the chemical. You can access our library of safety data sheets and download a copy by following the link below.
Please note that the '-' in HI- products should be removed from all searches to find the correct information.
Specifications
| Range | 0 to 350 ppm (mg/L) as CaCO3 |
| Resolution | 1 ppm (mg/L) |
| Accuracy | ±6 ppm ±6% of reading @ 25°C |
| Light source | Light Emitting Diode @ 470nm |
| Light Detector | Silicon Photocell |
| Method | Adaptation of the EPA recommended Method 130.1. The reaction between calcium, magnesium, and the reagents causes a red-violet tint in the sample. |
| Environment | 0 to 50°C; max 95% RH non-condensing |
| Battery type | 1.5V AAA Alkaline |
| Auto-off | After 10 minutes of non-use |
| Dimensions | 86.0 x 61.0 x 37.5 mm |
| Weight | 64g |
| Ordering Information | HI-735 Checker®HC is supplied with Total Hardness Low Range reagent starter kit (reagents 23 tests), sample cuvette and cap (2), 1mL graduated syringe with tip (2), plastic refilling pipette (1), 1.5V AAA alkaline battery (1), and instruction manual |
| Reagent set | HI-735-25 (25 tests) |
| Calibration set | HI-735-11 Certified Standard Kit |
| HI-731318 | cuvette cleaning cloth x 4 |
| HI-731315 | Glass cuvettes and caps x 2 |
| HI-731321 | Glass cuvette x 4 |
| HI-731225 | Cuvette cap for Checker®HC x 4 |
| HI-93703-50 | Cuvette cleaning solution |
| HI-740226 | 5mL graduated Syringe |
| HI-740157P | Plastic refilling pipette x 20 |
| HI-740144P | Pipette tip x 10 |
| HI-740143 | 1mL graduated syringe x 6 |
| HI-740036P | 100mL plastic beaker x 10 |
| HI-70436M | deionised water (230mL) |
| HI-70436 | deionised water (1G) |
Downloads
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.