Payment & Shipping Terms:
|Certificates:||CE And ROHS||Type:||Water Filter Parts, Portable/Handed|
|Warranty Tds Meter Tester:||3 Years||Resolution:||10ppm|
|Operating Temperature:||°C~50°C||Product Name:||Custom Logo Water Test Instrument Tds Meter Tds Monitor|
Does Temperature Impact TDS Measurements?
One final complication is that the conductivity of ions in water depends upon temperature. There are a number of factors that cause this effect, but one big one is simply that the ions are naturally moving around faster as they get warmer. When the same numbers of ions are moving faster, the apparent conductivity is increased. The relationship between conductivity and temperature is complicated and dependent on the solution being tested.
Pure water responds fairly linearly with temperature, with its conductivity rising by 4.55% for every degree centigrade (2.5% per degree Fahrenheit). Sodium chloride solutions have a smaller change, about 2.12% per degree centigrade. Tap and other natural waters have many different ions in them, and such systems sometimes respond nonlinearly with temperature changes, but not typically to as great of an extent as does pure water.
For this reason, nearly all conductivity meters simultaneously measure the conductivity and the temperature. The internal electronics then take the temperature into account, and normally provide a value that is "corrected" to what the conductivity would be at a standard temperature (25°C). Some use a fixed correction (for example, one manufacturer uses 2.1% per degree centigrade, another uses 1.9% per degree centigrade). More expensive units often allow the user to select the temperature coefficient (I'd use about 2-3% per degree centigrade for tap water). Others even allow nonlinear corrections to be used. If your meter allows that, I'd pick that option as it is likely a fixed correction that is optimized for fresh water systems (often called nLF). Some very advanced meters also allow nonlinear correction for ultrapure water. If your meter uses either of these nonlinear corrections, it will clearly say so in the provided manual.
In short, since conductivity meters typically correct for temperature changes, the conductivity of the water sample can be measured regardless of the temperature of the sample.
What Do the Units "ppm" Mean?
The units of measurement that TDS meters use are even more confusing than the name TDS. Conductivity meters (including TDS meters) always work by first measuring conductivity. Conductivity in solutions always has units that relate to resistance. Often those units are mS/cm (microsiemens per centimeter), but for solutions with higher conductivity, mS/cm (millisiemens per centimeter) is typically used (for example, normal seawater has a conductivity of about 53 mS/cm). For reference, the conductivity of totally pure water is 0.055 mS/cm.
manual of TDS Meter
ns one needs to take into account the tightly bound water molecules that get dragged along as well, so one cannot simply look at molecular weights or ionic radii. This drag due to the size of the hydrated ion is, for example, why lithium (Li+) is so much less conductive than sodium, which in turn is less conductive than potassium (K+).
"Can I Just Use a Multimeter to Measure Conductivity?"
No. Several factors make it impossible to accurately measure conductivity with a standard multimeter. The size and shape of the electrodes are significant, but more important is what happens at those electrodes. If a DC current is applied to seawater, numerous reactions take place when the ions hit the electrodes. Some ions will plate out on the electrodes, some may bubble off as gases, and the electrodes themselves may dissolve. These and other effects all serve to change the nature of the solution at the electrode, impacting the measured conductivity.
So how do conductivity probes get around this problem? They use an AC current rather than DC. Using fields that oscillate very rapidly, there is no overall movement of ions toward one electrode or the other. The ions move one way for a tiny fraction of a second, and then back the other direction for the second half of the cycle. Overall, the solution and electrodes stay unchanged and the conductivity is accurately measured. Modern conductivity meters use complex AC waveforms to minimize additional complications such as capacitance, which can interfere with simple conductivity measurements.
In practice, commercial conductivity probes have either two or four electrodes, with the four-electrode version being more resistant to fouling and other effects that can cause degradation of the measurement. The electrodes are made of nonreactive materials such as epoxy/graphite, glass/platinum or stainless steel. The choice depends primarily on the nature of the solution to be tested, but nearly any commercial unit will be suitable for tap water.
Item size: Approx. 15 * 1.6 * 1.6cm / 1.3 * 0.6 * 0.3in (L * W * H)
Item weight: Approx. 3g / 0.1oz
Button Battery Type: LR44 / AG13 / 357A / (not include)
Package list:1 * TDS Detection Pen
1 * factory standard package
1.Q: Why you choose us?
A:1. We are manufacturer tds meter for 8 years. The quality is very good while the price is lower.
2. We can customize according to your needs, with more direct communication and shorter delivery time.
2.Q:What's the delivery time?
A:Normally within 2 days when your quantity is no more than 1000 pieces.
3.Q:What is the MOQ if i need tds meter with my brand/Logo ?
4.Q:What is the warranty period on this item?
A:It has a 3 years warranty since the date of delivery.
5.Q:What if I need a Certificate of Calibration?
A:80% of our item have certification , Such as CE , ROHS , LFGB . But all certification is in favor of our factory name and model . If you need a certification by favor of your company name and model , Please contact with our sales and discuss the detail extra fees.
6.Q:Do you provide OEM,ODM, customized manufacturing service?
A:Yes, we warmly welcome your customized requirement, and we have designer who can realize your idea specifications on paper easily and turn them into the specific goods. We are sure to be your unique and reliable partner of OEM business. Thank you!
Contact Person: Carey Gao