Phosphate Ultra-Low Range (PPM) Reagent - 25 Tests - Hanna Instruments

The HI774-25 reagents are the consumable component of the HI774 Phosphate Ultra Low Range Checker HC system, a colorimetric photometer designed for low-level phosphate measurement in reef and marine aquaria. When phosphate control is a priority — as it is in most SPS-dominated systems — having a reliable, repeatable test method matters. These reagents are manufactured at Hanna's own production facility using high-purity chemicals, which helps ensure consistent reaction quality from sachet to sachet.

The HI774-25 reagents follow the Ascorbic Acid Method. Adding a reagent packet to your water sample initiates a reaction between phosphorus compounds and the reagent chemistry, producing a characteristic blue tint. The HI774 Checker HC then reads the intensity of that color and converts it to a concentration value expressed in parts per billion (ppb) of phosphorus. The measurement range covers 0.00 to 0.90 ppm phosphate, making this format appropriate for reef tanks where phosphate targets are typically kept below 0.10 ppm.

Because the reagents come pre-measured in individual sachets, there is no weighing, pipetting, or preparation involved. This reduces the chance of dosing error and speeds up the testing process. Each sachet is clearly labeled with a lot number and expiration date, so you can confirm reagent freshness and maintain a record for consistency. This pack contains 25 tests — enough for routine weekly monitoring over an extended period, or more frequent testing during periods of tank adjustment.