For monitoring the Physico-chemical parameters of the fish farming medium, we use a multi-parameter probe which is immersed all the time, and which transmits data in real-time. The problem is the accumulation of fouling on the sensors of the probe, which consequently affects the measurements !!
It may depend on each specific probe. Here are some ideas from YSI company. https://www.ysi.com/File%20Library/Documents/Technical%20Notes/T601-Care-Maintenance-and-Storage-of-YSI-6-Series-Probes-and-Sondes.pdf
When end you do your regular calibration against standards, or if you experience a decline in response for no good reason, you may note at what frequency might be appropriate before cleaning with distilled water, white vinegar or other suitable treatment, non-scarifying scrub, before replacement of membrane or other maintenance or rebuilding may be needed. In some instances, a screened enclosure that allows relatively free flow but restricts light and sediment entry may help in some environments. Some companies may offer a loaner or rebuilt replacement for times when your sonde or probe needs servicing. Many companies provide free technical support, and sometimes you can find that dedicated technician that will really help and not try to sell you a rebuild or costly replacement. At some point, a replacement or rebuild may be needed.
You can try and use copper tape (found at hardware stores). I have seen this used on many marine mooring instruments, including those around aquaculture sites. You can remove and change the tape every few weeks - a month.
Hello Omar,
I worked in medical laboratories for most of my career and we relied on sensitive, analytical instrumentation to determine disease processes. The results obtained guided physicians on patient care; hence, results needed to be precise and accurate. The instruments were usually immersed in all sorts of bodily fluids, waste, blood and various reagents, which could plug up or alter the probe effectiveness. Depending on the analytical method and type of instrument, we routinely cleaned the probes in various ways, sometimes after each patient sample if that was required. These ways included automatic probe rinses (with water, bleach, alcohol or a combination thereof); mixing and agitation so debris could not settle on the probe; the use of pre-filters to sift gross debris/sediment out of the sampling fluid; and also manual cleanings with special cleansing agents. Manual cleanings were always done according to a strict schedule (eg, once a week or month) when the instrument was turned off or in a non-sampling mode. I'm not sure if any of these methods are feasible for your system, or how accurate your results need to be, but some of these ideas may help keep your probe in good running order? Stacia
And, we always re-calibrated the instruments and did a system check on the results after any probe cleanings, as mentioned by William F. Hansen above. This ensured the system was running correctly afterward and the cleaning was effective. Another idea is to phone the instrument manufacturer/vendor, they probably have encountered similar problems with the probe from other clients, and can share satisfactory methods of debris control.
Omar Izzabaha , If your instruments have external power coming in, there is the option of using UV LEDs. I have been testing this in the field and it seems to prolong the time CTD measurements are reliable for. Reach out if you want more info!
Thank you Mathieu Dever, it's a very interesting idea.
Yes the instrument is equipped with external power (photovoltaic), but is the UV LEDs will not affect the rays emitted by the sensors?
Omar Izzabaha I have only tested it on CTDs for now. I suppose it would be applicable to optical sensors as well, as long as measurements and UV LEDs are out of phase. Although an oxygen sensor foil might be bleached by the UV light. A lot depends on the setup I suppose !
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