It's that time of year, time to pull your water quality instruments out of storage and get them ready to take out in the field. Is your sonde field ready? Over the course of the next two weeks, we will be sharing with you 7 tips, straight from the experts to ensure your sonde is field ready, which in turn, makes you ready for the sampling season.
Tip #1 Always Inspect the Condition of Your Sensors
It’s important to inspect the condition of your sensors before you start your maintenance and calibration procedures. There’s no sense in taking the time to calibrate if you have damaged equipment or obviously defective probes. Take note on how your sensors were stored prior to use. Optical probes like turbidity, chlorophyll, or blue-green algae, as well as conductivity probes, can be stored wet or dry and suffer no adverse effects but the performance of your DO and pH probes will be compromised if they dry out. Make sure both of these are stored in moist environments when not in use.
pH probes that have dried out may not look any different than one that was stored properly so that’s why it’s important to take notice of the state of your equipment before you get started. Just looking at the probe doesn’t tell the story, but observing HOW the probe was stored will clue you in that there may be a problem.
If the pH probe is accidently stored dry, try to rehydrate it by soaking it in a pH 4 buffer for several hours and then attempt calibration. If calibration fails after the rehydration attempt, then your pH probe will need to be replaced. If the bulb is broken, there is no reason to attempt calibration. There is no way to repair or reattach a bulb to a broken pH probe. The probe will need to be replaced. Dirty pH probes can be cleaned by soaking them in a bleach/water solution. Consult the manuals for complete cleaning procedures.
The age of the probe is another visual inspection to make note of. All YSI probes and instrumentation in general have lot numbers or serial numbers which tell us the age of the equipment. They begin with two numbers and then a letter. The two numbers indicate the year of manufacture and the letter indicates the month. A is for January, B is February, C is March and so. We do skip the letter “I” however and December is denoted by the letter M.
Example: A pH probe with the lot number 11E was manufactured in May of 2011.
pH probes have a general lifespan of 12 to 18 months and that’s whether you’re actively using it or not. If a pH probe is over a year old, pay closer attention to calibration if the probe appears to be in good condition and is clean but you have slow response or a questionable slope, then the problem may be the age.
Now, let's talk about the optical dissolved oxygen probe. Check the optical membrane cap for excessive scratches in the painted surface. The paint is designed to help with ambient light rejection. If too much of this paint is missing, it can lead to erratic readings and also be sure the ODO membrane has not dried out. As a rough estimate, if the ODO cap has lost 1/3 of its paint, you may need to replace it. You’ll likely have difficulty calibrating and experience jumpy readings if too much of the paint is removed. Replacement caps can be purchased and easily installed by our customers. No need to send it in for this service. If the optical DO membrane has dried out, rehydrate it by submerging it in tap water for several hours, 4 to 6 should be sufficient. Then try to calibrate it and note the stability of your probe’s readings. If the results are questionable, replace the ODO membrane.
YSI always suggests taking a look at the manuals provided with your probes or instruments. Proper handling and storage recommendations can be found there as well. If you have misplaced your YSI manual, you can download another copy here.
Feel free to watch the full webinar "Gearing Up For The Sampling Season."
Additional Blog Posts of Interest:
YSI Expert Tip #2: Properly Maintain Your Instrument Sensor Connections.
YSI Expert Tip #3: Always Check Your Batteries and Power Supply.
YSI Expert Tip #4: Always Keep Firmware & Software Updated.
YSI Expert Tip #5: Properly calibrate All Your Sensors Prior to Collecting Data.
YSI Expert Tip #6: Finalize Your Sonde Settings Prior to Leaving for the Field.
YSI Expert Tip #7: When Going Into the Field, Always Bring a Field Survival Kit.