Water Quality Frequently Asked Questions
Click here to see a list of categories for water quality instruments.
pH FAQs
What if I have a water ionizer?
You will likely want to measure the pH and ORP. Please make sure you select a meter capable of both measurements and be sure to purchase the required solutions for best results.
Why is calibration needed?
Calibration is needed frequently in pH meters to standardize the electrode. Over time the measurements will drift; calibration will correct for this drift so you can accurately measure your pH.
What Solutions do I need?
For best results we recommend pH buffer 4, 7, and 10 as most meters will recognize these solutions. We recommend cleaning and storage solution to maximize the life of your electrode. We also offer other calibration solutions to accommodate special applications and our higher end meters which can accept these solutions.
How often should the meter be calibrated?
The general rule of thumb is to calibrate your pH meter once per week. For greater accuracy it is recommended to calibrate more frequently. For best accuracy you would calibrate prior to each test.
How do I calibrate my pH meter?
Most of our meters are very similar to calibrate and have automatic buffer recognition. Typically you would calibrate with pH7 first, then pH4 and pH10 being sure to rinse to avoid cross contamination between each calibration.
How should a ph meter be stored?
For best results and longevity of your electrode we recommend storing your electrode in a pH storage solution. DO NOT USE DEIONIZED OR DISTILLED WATER.
How long does a pH probe last?
Most pH probes will last 6 months to 2 years. Proper maintenance of your pH probe is the best way to maximize the life of your pH electrode.
When do I replace the pH probe?
When reading reacts unstable or sluggish it may be time to replace your electrode. If you can no longer calibrate the electrode, it is time to replace it.
Which meter do I need?
Depending on your application there are many pH meters available.
The testers are the least expensive option. These are generally the least accurate and do not have special purpose electrodes available but they are very popular because of their low cost. They are accurate enough for most users.
Basic handled meters will offer a larger screen than the testers and will offer greater flexibility with special purpose probes.
High-end handheld meters vary but many of them will offer PC connectivity, datalogging with date stamp to meet GLP (good lab practice), and very high accuracy.
Please contact an Instrumart Engineer to help select the correct meter for you.
ORP FAQs
Can I calibrate ORP?
Some meters allow you to calibrate ORP but many do not allow calibration. Testing solutions are available to verify your ORP reading but it is not accurate enough to be used as a calibration standard.
What Solutions do I need?
We recommend pretreatment solutions, cleaning solution and test solution.
What do the reducing and oxidizing solutions do for orp?
They pretreat the ORP electrode for optimal speed when taking readings. Also, they keep the platinum from bonding with minerals in the water
How often should it be cleaned?
It is imperative to keep the ORP tip clean to get proper readings and quick response.
Why am I not getting the ORP readings I expect?
Alkaline water has many minerals that will bond to the electrode if not properly maintained. The probe must be clean at all times in order to get the correct reading. It may be possible that your water ionizer is not producing the desired –mV water. Please consult the manufacturer on how to clean or service the unit.
Conductivity/TDS/Salt FAQs
Which solutions do I need?
The most common solutions are 84uS, 1413us and 12.88mS. Please refer to the manual of the instrument you are purchasing to make sure you select the proper calibration solutions.
How often should I calibrate?
Conductivity instruments do not need to be calibrated as often as pH meters. We would recommend a calibration at least once per month.
Is any special care/maintenance required?
Conductivity meters need to be kept clean but they can be stored dry.
Dissolved Oxygen FAQs
What do I need for maintenance and calibration?
Zero oxygen solution is available for calibration. Some of these probes require maintenance electrolyte solutions and replacement membranes. Please refer to the manual to verify which solutions,membranes and caps are recommended for your meter.
What technologies are available for DO measurement?
Here at Instrumart we offer all available technologies; Polarographic, Galvanic, and Optical. Please call an engineer to determine which technology is right for your application.