This week we continue to talk about various ways to tackle a common issue with long term monitoring instruments – biofouling. We’ll focus on providing tips on how to fight fouling and how to collect the highest quality data over the course of a long-term sonde deployment period. Using a combination of our suggestions, you’ll be able to significantly reduce the frequency at which your team must travel to field sites to clean and maintain sondes and water quality sensors.
Over the course of the past few weeks, we have discussed methods of biofouling prevention, including copper based anti-fouling paint and using copper components on your instrumentation. This week we will provide your third tip to tackle this issue.
Protect Sensing Surfaces with Mechanical Wipers & Use Simple Accessories to Save on Cleanup Time
We realize everyone’s number one end goal is to collect accurate and complete data sets. The ability to minimize field site visits may be secondary, but still important. Luckily, there is a host of accessories to assist with deployment longevity.
Last summer one of our very own Application Engineers’ deployed a few prototype instruments in the Chesapeake Bay. The Chesapeake Bay is an estuary along the Atlantic that acts as the drainage basin for more than 150 rivers and streams. The deployment was only for a week, so it was decided that no antifouling measures would be taken with the instruments. What we learned? This was an absolutely terrible mistake!
The only areas that were not covered were the faces of the sensors that were wiped. The biofouling that accumulated in that short time was great. This was the type of biofouling that felt soft to the touch, kind of like wet velvet, but did not want to come off with brushing or soapy water. Our Applications Engineer ended up having to soak them in soapy water for several days to remove the growth, and it still took several hours to clean everything.
So we suggest the number one accessory to mitigate fouling would be a mechanical wiper or wiping system. That’s the first line of defense against bio growth for sensors.
A wiper is a mechanism that sweeps over the sensing surfaces between measurements. In older sonde platforms, each optical sensor had its own wiper that had a soft pad to sweep across this area. However, newer sonde technology uses a centralized wiper with more torque and stronger bristles to clean a whole suite of sensors simultaneously. This wiping design is more robust because it offers more thorough cleaning and there’s only a single brush to maintain.
Using a mechanical wiper will keep the sensing surfaces clean of debris, but what about the rest of the instrument? There are other accessories to help with fouling and post deployment clean up. Most require basic tools like scissors, an xacto blade, and sharpie pen to apply.
Items like shrinkable plastic sleeves can form a protective layer between your instrument and the environment and make cleanup much easier. This works well in soft fouling environments, where things like small aquatic worms, mud, and some algae would otherwise coat your sonde from top to bottom. For hard biofouling, these sleeves need a layer of copper tape or duct tape over them because the barnacles can penetrate the plastic.
Copper alloy screens and guards work well to keep biofouling out of the protected areas. These items may still need some brushing post deployment, but typically will not need a long acid soak.
As we learned in Tips 1 and 2, when items like copper tape, copper alloy guard, and a wiper have been applied, post deployment cleanup is much faster. Typically, the taped areas can be sliced and peeled away, eliminating an acid soak and several hours of scrubbing and cleaning.
Other areas that were not protected may need a soak, followed by a scrub with a soft plastic bristled brush and clean water rinse. These would include areas like topside connectors, the bail, and securing items.
Having just a few of these accessories will save you hours of cleaning.
Let’s recap - a wiper is your best option for maintaining clean sensor faces, while plastic sleeves and copper tape or duct tape make clean up faster. Also, copper accessories help to detour organisms from settling on your instrument.
Next, Tip #4 – Always Keep Up to Date with New Sensor Techonology.
A huge thank you to YSI Product Manager, Brandon Smith, YSI Marketing Specialist, Patrick Beatty, YSI Technical Support Team Lead, Tom Moeggenberg and YSI Application Engineer, Tiffany Shirmer for providing the information found in this post.
Additional Blog Posts of Interest:
7 Tips to Fight Fouling and Extend Sonde Deployments | Tip #2
7 Tips to Fight Fouling and Extend Sonde Deployments | Tip #1
Extend Your Water Quality Sonde Deployment Times with Wiped Sensors [Case Study]
The EXO Wiped Conductivity & Temperature Sensor Helps Eliminate Biofouling