Method

advantage

disadvantage

Jackson Candle Turbid meter

-Water poured into tube.

-Reading taken when candle burning under tube can

no longer be seen.

(Historical method.)

No longer a standard method.

Can’t measure < 25 JTU (25 NTU).

Turbid meter (Nephelometer)

-Beam of light passed through water sample.

-Amount of light scattered at a 90˚ angle measured.

Extremely accurate.

Some are portable.

Can measure very low turbidity.

Expensive.

Easily damaged.

Requires power source.

Requires calibration.

Secchi Disk

-Black and white disk lowered into water.

-Maximum distance at which disk can be seen recorded.

Low cost.

Portable.

No consumables.

Easy to learn

Less accurate.

Can’t be used in shallow water or swift currents.

Not applicable to small sample size.

Turbidity Tube (Transparency Tube)

-Combination of Jackson candle and Secchi disk methods.

Low cost.

Portable.

No consumables.

Easy to learn.

Suitable for all water sources.

Less accurate.

Can’t measure < 5 NTU.