Count tests, not packets.
Keep low-range iron testing moving with the right refill for your HI97746 photometer. Choose HI93746-01 for 50 determinations or HI93746-03 for 150. Each determination uses two packets: one for a reagent blank and one for the water sample—not one packet per result.
Official Hanna reference packaging. The printed 09/2022 date is illustrative, not the expiration date of supplied stock.
For the HI97746 low-range iron method
The HI97746 measures 0.00 to 1.60 mg/L as Fe using TPTZ chemistry, which develops a violet color. Match the reagent code and method rather than selecting by the word iron alone: these are not HI746 Checker reagents or the HI93721 high-range iron chemistry.
Is this the right chemistry for my sample?
Use for the method's colorimetric determination of iron in water samples. The HI97746 manual specifies sample pH between 3 and 4 and lists metal-ion and nitrite interferences; for example, copper above 0.6 mg/L and cobalt above 0.05 mg/L can interfere. Review the complete interference list for your matrix before relying on a result. Do not assume a general seawater, wastewater or total-digestion application from the reagent name.
Which pack fits my workload?
HI93746-01 supplies 50 tests; HI93746-03 supplies 150 tests using the same HI93746-0 chemistry. Choose by the number of results you expect to report within the supplied reagent's shelf life. A larger pack does not increase the measuring range. Order quantity 1 for one selected reagent pack.
What must I have separately?
These are reagent-only refills. Have the HI97746 photometer, clean cuvettes with the specified caps and stoppers, graduated mixing cylinders and deionized water available separately. CAL Check standards are separate instrument-check products, not the reagent blank and not a replacement for sample reagent.
Why the blank needs its own packet
For the HI97746 procedure, prepare 25 mL of deionized water with one HI93746-0 packet and shake vigorously for 30 seconds; transfer 10 mL of this blank to the cuvette and zero. In another cylinder, prepare 25 mL of sample with the second packet and the same mixing step. Transfer 10 mL of reacted sample and use the instrument's 30-second countdown before reading. Follow the linked method manual for the full sequence, temperature guidance and interferences.
Keep the optical measurement consistent
Use clean, dry cuvette exteriors and remove bubbles before inserting a cuvette. Observe the method timing and discard the reacted sample promptly after measurement. Check the lot and expiration markings, and review the US Safety Data Sheet before handling or disposal. Hanna classifies these reagents as Dangerous Goods for ground shipment only.
Frequently Asked Questions
Why are the packs 50 and 150 tests, not 100 and 300?
The HI97746 procedure consumes two HI93746-0 packets for each determination: one in a deionized-water blank and one in the sample. Current US retail packs and the HI97746 manual specify HI93746-01 as 50 tests and HI93746-03 as 150 tests. Packet counts must not be treated as test counts.
Does the larger pack measure a higher iron concentration?
No. Both packs use the same TPTZ chemistry. On HI97746 the range is 0.00 to 1.60 mg/L as Fe; pack size changes the number of determinations, not the range.
Can I zero with untreated sample instead of a reagent blank?
Not for the HI97746 procedure. Prepare a separate blank from 25 mL of deionized water plus one packet, mix as directed and transfer 10 mL to the cuvette for zeroing. The sample is prepared separately with another packet.
Which meter is this buying guide based on?
The HI97746 iron low-range photometer. Its method manual explicitly lists both pack codes. If using another Hanna photometer, confirm HI93746 chemistry and the exact procedure in that instrument's manual rather than assuming all iron methods are interchangeable.
Are these suitable for every water matrix?
No universal matrix claim applies. The HI97746 method requires sample pH between 3 and 4 and lists interferences including copper, cobalt, nickel, nitrite and other ions at stated concentrations. Read the complete manual for your sample; marine or complex matrices need method-specific assessment.
What equipment is not included?
The HI97746 meter, cuvettes, caps, stoppers, mixing cylinders, deionized water and CAL Check standards are not part of these reagent refills. Have the accessories required by the method available before testing.
How should I plan mixing and reaction time?
Prepare the blank and sample separately, shaking each vigorously for 30 seconds. After the reacted sample is placed in the meter, use the 30-second reading countdown. The manual gives the complete sequence and temperature-related timing guidance.
What should I check when the pack arrives?
Check the catalog code, packet lot and expiration markings and condition of the packaging. Review the HI93746-0 US Safety Data Sheet and follow your handling and waste procedures. Hanna specifies ground shipment for these Dangerous Goods reagents.
