The National Pool Industry Research Center in San Luis Obispo, Calif., studied the overall performance of selected test kits. The absolute value of the errors was averaged for each kit. The kits with the lowest average error are the most accurate. The chart below summarizes the accuracy results for each test kit.
| OVERALL ACCURACY SUMMARY | ||||||
| Kit | Free Chlorine | Total Chlorine | Total Alkalinity | pH | Calcium Hardness | Average |
| (Percent deviation from lab value) | ||||||
| AquaChek (strips) | -21.8 | -32.1 | 6.3 | -30.7 | 14.6 | 21.1 |
| AquaChek(DPD) | -13.7 | -27.5 | 11.2 | 20.2 | 51.7 | 24.9 |
| Guardex (DPD) | -27.6 | -45.2 | 16.5 | 6.2 | N/A | 23.9 |
| Guardex (OTO) | -16.2 | -34.8 | 21.8 | 9.2 | N/A | 20.5 |
| LaMotte (strips) | -15.5 | -27.5 | -3.9 | -0.3 | 43.4 | 18.1 |
| LaMotte (DPD) | -13.8 | -26.9 | 17.4 | 9.6 | 40.8 | 21.7 |
| Pentair (DPD) | -31.0 | -38.6 | -0.4 | 28.4 | N/A | 24.6 |
| Pentair (OTO) | N/A | -34.5 | -3.5 | 20.2 | 52.8 | 27.7 |
| Pentair (strips) | -43.9 | -41.8 | -10.4 | 10.3 | 14.5 | 24.2 |
| X-Kit 1 (DPD) | -0.7 | 0.1 | 15.4 | 7.2 | 59.9 | 16.6 |
| X-Kit 2 (strips) | -45.0 | N/A | 1.1 | -28.1 | N/A | 24.8 |
| X-Kit 3 (DPD) | 17.3 | -16.8 | 14.7 | -2.5 | 60.9 | 22.4 |
| Jack's Magic (DPD) | -8.0 | -27.5 | -4.6 | 35.7 | 18.6 | 18.9 |
| Palintest 9(photometer) | -16.2 | 0.0 | 27.5 | 37.5 | 13.4 | 18.9 |
| Average | -18.3 | -29.4 | 6.3 | 6.6 | 39.7 | 22.3 |
