Distance from Bottom of Tube (cm) |
NTUs |
<6.25 | >240 |
6.27 to 7 | 240 |
7 to 8 | 185 |
8 to 9.5 | 150 |
9.5 to 10.5 | 120 |
10.5 to 12 | 100 |
12 to 13.75 | 90 |
13.75 to 16.25 | 65 |
16.25 to 18.75 | 50 |
18.75 to 21.25 | 40 |
21.25 to 23.75 | 35 |
23.75 to 26.25 | 30 |
26.25 to 28.75 | 27 |
28.75 to 31.25 | 24 |
31.25 to 33.75 | 21 |
33.75 to 36.25 | 19 |
36.25 to 38.75 | 17 |
38.75 to 41.25 | 15 |
41.25 to 43.75 | 14 |
43.75 to 46.25 | 13 |
46.25 to 48.75 | 12 |
48.75 to 51.25 | 11 |
51.25 to 53.75 | 10 |
53.75 to 57.5 | 9 |
57.5 to 60 | 8 |
Over the top | 6 |