Overview of the Kyoritsu Packtest – Phosphate Phosphorus (low range)
Kyoritsu PACKTEST low-range phosphate test tubes measure the phosphate levels in a water sample. They are supplied directly from Japan in boxes of 40 tubes, so they need to be bought in relatively large volumes. The user must first remove a small plastic pin from the tube to open a small aperture, then squeeze the tube to expel the air, invert the tube, immerse it in the sample and then release the tube to draw in the sample. Then, wait 5 minutes for the colour change to develop. The optional PACKTEST square cup can be used to ensure a consistent sample volume. Due to the need to estimate which colour the sample matches, this method is considered semi-quantitative.
Suitability for monitoring purposes
| Monitoring purpose category | Likely Tier(s) | Suitability |
| Engagement: Education and raising awareness | 0-1 | ✓ |
| Surveillance: Ecosystem health screening | 1 (2) | ✓ |
| Investigation: Helping to target further action | 2 (3) | ✖ |
| Evaluation: Assessing the impact of actions | 2 (3) | ✖ |
Details: Measures phosphate in the range 0 – 2 mg/L as PO4 (0.05, 0.1, 0.2, 0.5, 1 and 2 mg/L) and 0 – 1mg/L as P 0.02, 0.05, 0.1, 0.2, 0.5, 1 mg/L). Different colour charts are given for P vs PO4 – so ensure the correct one is used. Accuracy is not stated but assumed to be +/1 half a ‘step.’
Data system: N/A. Results are not stored on a device, so the user must record and store them.
Cost: VERY LOW. Around £50 for a box of 40 tests (c. £1.25/test) – bulk discounts are available, but import duty and shipping costs are extra.
Ease of use: EASY. Reagents are contained in each capsule so users do not come into direct contact with them.
Quality control: Local coordinators are responsible for quality control. Measurement is likely affected by extremes of temperature and highly coloured samples.
Coverage / scale: Can be used anywhere – currently used internationally by Freshwater Watch and Water Rangers
Health & safety: No known issues; users should not come into contact with reagent or reacted sample.
Case studies featuring this method: Earthwatch: Great UK Waterblitz