YSI ADV6600 - Manual (Page 152)

Section 11. Troubleshooting
ADV6600
Y S I
Environmental
Page 142
• Be certain the sampling volume of the instrument is sufficiently spaced from boundary and that
there is nothing blocking or partially blocking one or more acoustic beams.
• Consider any possible influences of the deployment environment; particularly flow interference
from nearby underwater structures.
• Consider the orientation of the probe with respect to the flow direction to be sure the probe is
not causing flow interference in the sampling.
11-3.3. Seeding for Scattering Environments
In most applications, there is sufficient scattering material naturally present for ADV operation.
However, if the velocity data appears “noisy”, a lack of scattering material in the water may be the
cause. This can be confirmed by running the Beam Check portion of the ADVantage 6600
software. The data can be recorded to a file and sent to YSI Customer Support for further
interpretation and comment.
An ideal seeding material should have the following qualities:
• Neutrally buoyant (to remain in suspension for a long period of time).
• Mean particle diameter of 10-20 µm (for peak sensitivity of the acoustic signal).
• Inexpensive, readily available, with no adverse effects on the sampling environment.
The best seeding material we have located (from an acoustics point of view) are hollow glass
spheres with a mean diameter of approximately 10 µm and a mean density close to that of water.
Quantities can be purchased from the manufacturer at the address below:
Potters Industries Phone: (610) 651-4700
Valley Forge, PA USA Internet: www.pottersbeads.com
Part name: Potters Spherical
For most applications, a more practical seeding material is lime or pulverized limestone (the chalk
commonly used on athletic fields). Large bags are inexpensive and readily available from most
hardware stores. While not perfect, the acoustic performance is sufficient for most applications.
Caution: repeated addition will gradually increase the pH in a sample.
11-4. Water Quality Sensor Problems
The following table provides information on problems you may have with 6600 sensors and actions
that may be take to cure the problem. The REF column lists sections in this manual where
additional relevant information may be found.