Resolve lower-range hardness without mixing up the chemistry.
Replenish your total-hardness workflow with a complete, range-specific reagent pack for 100 tests. HI93735-00 is the low-range chemistry for 0–250 mg/L as CaCO₃: a focused refill for a compatible photometer, not a different pack size of another hardness method.
Official Hanna HI93735-00 product photograph. Packaging, labels, lot markings and printed dates are illustrative, not a promise of current-stock expiry or an itemized pack inventory.
Match the refill to the complete method
Choose LR for 0–250 mg/L as CaCO₃. The HI97735 has separate LR, MR and HR programs, with a different Reagent A for each range. Select the matching method and reagent set together; overlapping ranges do not make the chemistries interchangeable.
Measure combined calcium and magnesium hardness
This method reports total calcium plus magnesium hardness on a calcium-carbonate-equivalent basis. A reading in mg/L as CaCO₃ is not a direct calcium-ion concentration, a calcium-only hardness result or a measurement of total dissolved solids. Keep the reporting basis consistent when comparing results or tracking changes in water treatment.
One complete range-specific refill
The 100-test pack supports the LR method using liquid HI93735IND-0 indicator, liquid HI93735A-LR Reagent A, liquid HI93735B-0 buffer and HI93735C-0 fixing-reagent powder packets. Test capacity describes complete determinations; it does not specify retail bottle counts or bottle fill volumes. The photometer and sample-handling equipment are separate requirements.
Prepare the cuvette before zeroing
For HI97735, select Total Hardness LR. Add 0.5 mL of unreacted sample and 0.5 mL of liquid HI93735IND-0 to the cuvette. Use a plastic pipette to fill to the 10 mL mark with HI93735A-LR (the required-reagents table lists 9 mL). Add two drops of HI93735B-0, replace the plastic stopper and cap, and invert five times. Seat the cap notch securely in the holder groove, then press Zero. Do not zero with untreated sample.
Add the fixing reagent only after zeroing
Remove the cuvette, add the contents of one HI93735C-0 packet, replace the plastic stopper and cap, and shake gently for 20 seconds. Reinsert with the notch correctly seated and press Read. The result is displayed in mg/L as CaCO₃. This is a concise HI97735 workflow reminder, not a substitute for its instruction manual or the procedure for another instrument.
Set up a repeatable measurement
Have a compatible photometer, suitable cuvette with plastic stopper and cap, accurate 0.5 mL sample and indicator measurement equipment, a plastic filling pipette, scissors and a lint-free wipe ready. Keep the optical surfaces clean and follow the instrument’s cuvette handling instructions. The manual identifies excessive heavy metals as a possible interference; investigate an unusual sample matrix rather than assuming an out-of-range result is valid.
Compatibility and range selection
HI97735 section 8.1 documents this exact HI93735-00 set and procedure. The approved model evidence also lists HI93735-00 for HI83300 and HI83399 total-hardness LR methods; use each instrument’s own method instructions. This page is a single LR reagent set, not the HI93735-0 mixed-range assortment and not the HI93720 calcium-hardness or HI937521 calcium-ion chemistry.
Handle every component as directed by its SDS
Read all four current US component safety data sheets before use. The indicator can irritate skin and eyes. Buffer B is combustible, irritates skin and eyes, and is harmful to aquatic life with long-lasting effects. Fixing reagent C is harmful if swallowed or inhaled, causes serious eye damage and may cause organ damage through prolonged or repeated exposure. Wear the protective equipment required by the SDS, avoid dust and splashes, keep buffer away from ignition sources, and follow local disposal requirements. The safety documents are component-specific; they are not an air-shipping authorization.
Keep consumable planning separate from stock promises
Plan replenishment by complete tests while allowing for your quality-control use and laboratory procedures. Use the expiry and storage instructions supplied with the actual lot; dates visible in the product photograph are not current-stock expiry. No bottle quantity, shipping weight, dispatch date or carrier permission is inferred from the photograph or per-test doses.
Frequently Asked Questions
What does this reagent pack measure?
HI93735-00 measures total calcium plus magnesium hardness over 0–250 mg/L as CaCO₃. Results are expressed as calcium carbonate equivalent, not as calcium ions or total dissolved solids.
Is this just another pack size of the other hardness ranges?
No. LR is a distinct range-specific chemistry using HI93735A-LR. The other total-hardness ranges use their own Reagent A and instrument programs. Choose the method that covers the expected sample concentration; do not swap Reagent A across ranges.
How many tests are supplied, and are bottle volumes specified?
The manufacturer specifies sufficient reagents for 100 complete tests. Retail bottle counts and fill volumes are not established here. Per-test quantities describe the analytical method, not the number or size of containers supplied.
Is HI93735IND-0 a powder or a liquid?
In the current HI97735 method, HI93735IND-0 is a liquid indicator dosed at 0.5 mL per test. Reagent A and buffer B are also liquids; HI93735C-0 is the powder packet added after zeroing. Do not follow an old powder-indicator assumption.
When do I zero the HI97735?
Zero after combining 0.5 mL sample, 0.5 mL indicator, HI93735A-LR to the 10 mL mark and two drops of buffer B, then inverting five times. Only after zeroing should you add one C packet, gently shake for 20 seconds and read. Follow the full instrument manual for handling and operation.
Which instruments can use this exact set?
The HI97735 manual lists HI93735-00 for its Total Hardness LR method. The approved HI83300 and HI83399 method evidence also lists the set. Verify the exact method on your instrument and follow its own instructions; a reagent listing is not universal photometer compatibility.
What else is needed and what can interfere?
A compatible photometer, suitable cuvette, stopper and cap, accurate small-volume measurement equipment, plastic filling pipette, scissors and a clean optical wipe are needed. Excessive heavy metals can interfere. These reagents do not turn a calcium-only method or a dissolved-solids meter into a total-hardness measurement.
What safety, transport and expiry information should I use?
Use the four linked US component SDS and the labels on your actual lot. Indicator and buffer cause irritation; buffer is combustible; fixing reagent C has ingestion, inhalation and serious-eye-damage hazards. Shipping classification and carrier acceptance require appropriate review; no air permission or blanket non-hazardous claim is made. Photograph dates are illustrative, not current-stock expiry.
