For the past two weeks, we have been talking about various ways to tackle the common issue – biofouling. This week, we will continue that discussion with tips 4 & 5.
This blog series focus is on helping you, by 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.
Take Care of Your Instrument and it Will Take Care of You
Accurate and complete data sets are drivers for investing in environmental monitoring platforms.
Let’s use the analogy of maintenance for your car as a comparison for your monitoring platform. There’s regular cleanup and tuning, and then there are things you need a certified expert to perform.
Instrument manufacturers provide guidelines for maintenance because they have an awareness of the items that may need special attention. Think of this like your car’s tune up. The mechanic will change out belts, lube fittings, and make recommendations based on their diagnostic analysis.
When you send your water quality instruments back for a preventative checkup, an expert technician will inspect items like internal o-rings, internal torque adjustments, perform power consumption tests, pressure tests, and specification testing of the system.
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Most people would not buy a car and then never wash it again after they leave the dealership. The same is true for your monitoring platform. For example, after a heavy snow or good 4x4 session in the mud, chances are you will probably wash off your grocery getter before summer or your next off road experience. This is when you notice scratches, dings, rust, a nail in your tire, or low tires. The same is true for your instruments. Cleaning in between deployments is imperative to minimize fouling and also helps to create a habit of inspecting your investment.
Regular cleaning helps to minimize biofouling by removing biofilms that micro organisms create. When micro organisms adhere to your instrument’s surface they become problematic in a few ways:
- They condition the instrument surface, provide an enzymatic interaction for exchange of nutrients, protection against environmental stress, and increase resistance to biocides
- Once formed, they change the instrument surface chemistry which can lead to macro organism growth, like barnacles
- They also interrupt ion flow, acting like a diffusion barrier, which can lead to localized corrosion
So what are the typical tools needed to clean?
- Mild dish soap
- Dish brush
- Plastic putty knife
- Clean water, tap water is okay
- Non-abrasive scouring pad
- Manufacturer issued CT brush, grease, and syringe
- White Vinegar or 1 molar HCl
For most deployments, soap and elbow grease can typically remove most soft fouling. Soft fouling would include muds, silts and worms. You can use a brush to get the bulk of the fouling off, then clean each sensor more thoroughly with a scouring pad.
For sites with harder fouling, like barnacles, a short soak in 1 molar hydrochloric acid, typically 10-15 minutes helps to break down the organisms to a point where a brush and scouring pad will work. Be sure to wear cut resistant gloves, these guys can be sharp and you will feel every little razor cut once you make contact with saltwater. If HCl is not available, white vinegar will also break down carbonates, but may take longer, like hours or overnight. Rinse well with clean water after soak.
After all cleaning has been performed; carefully look over your instrumentation. Check the cable’s integrity and connectors. Ensure the connectors are free of debris. You can apply the grease with your bare fingers to areas like o-rings and connectors. This enables you to catch nicks or grit that could compromise seals. Inspect integrity of the securing items like the bail, carabiners, and chain.
Now, all other water quality sensors plug into a sonde, while your depth or level sensor is built into the sonde body itself. That makes maintaining your depth sensor easy to forget. The depth port is a hole in your sonde where water flows through the instrument and to the internal depth sensor. This port can get fouled just like the rest of your sonde. You may notice from your data, the depth increasing, or you may notice an unexpected measurement when the sonde is on the lab bench. These are both signs of depth port blockage.
Fill the small syringe supplied by the manufacturer with clean water. Force the water into the depth port hole and watch the other hole for water exiting. If it doesn’t, then there may be a blockage. If soft fouling is suspected, then try soaking the area in warm soapy water then repeat the clean water cleanings. If hard fouling is suspected, try soaking the area in some white vinegar. Do not try to clean this area with a brush or pipe cleaner. Follow up the vinegar soak with several clean water flushes.
Lastly, another crucial item to look over is your wiper. This is your first line of defense against fouling. We can’t stress enough how important it is to check your brush for splay, or check your pads for wear and tear. Too much splay or wear can drastically reduce your wiper’s effectiveness. If you have a wiped conductivity sensor, then too much wiper brush splay can also cause ineffective grooming of the conductivity cells. Wiper brush/pad replacement is governed by the site, season, and sensor payload. Low fouling sites may get months of life, while other sites may need changing after only weeks of deployment.
So to recap, this tip covered wipers, maintenance, and brushes. Cleaning instruments well in between deployments and following the manufacturer’s guidelines for maintenance will help to protect your investment and give you confidence in your data.
Next, Tip #6 – Don’t Neglect the Field Site Infrastructure!
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 #4
7 Tips to Fight Fouling and Extend Sonde Deployments | Tip #3
7 Tips to Fight Fouling and Extend Sonde Deployments | Tip #2
7 Tips to Fight Fouling and Extend Sonde Deployments | Tip #1