I agree with you dear Farid Benyahia. Here is a link for Hanna pH meter:-

https://hannainst.com/ph

We have a lot of years of experience in field water quality measurements, if your instrument is not sturdy or with a good quality technology, it will just make you loose time and money.

I recomend the YSI instruments (I work in the mexican goverment, there is no personal interest in this) for example, look at this site: https://www.ysi.com/pro20 or a similar one. Good luck!

I think both of instruments Hanna and Ysi are good, but Hanna is cheaper than Ysi

Best Regards

We use for fieldworks horiba U-52(53). multi-parameter water quality meter

You can measure these parameters easily by using pocket pH, Turbidometer, EC and Thermometer available in market, but be sure you calibrate the instrument before measurement. There are other than Hanna seems to me better but right now I cannot remember the name to suggest you.

Just remember if you can't compromise with durability, then go for good instruments such as Hach, though with higher price.

Hach HQ40d is nice for measurement DO pH Ec. WTW 340i is also good and I used both of them for 10 years indeed calibration & maintenance in place.

But pertaining to the costs of these US - German products and budget issues, I'm using AZ 86031 Handheld IP67 Combo PH/COND./SALT/D.O Multi parameter.

For TDS be careful that all instruments multiple the EC number to 0.5 as default nlf coefficient. For measuring TDS you have to test TDS by gravimetric method to reach the adopted nlf of your water sprit. In other words the nlf for different water bodies is different less or more than 0.5 which I reached an nlf of 0.63 for Cheshmehkileh river (Tonekabon City-Iran) during One year water monitoring and measuring TDS by gravimetery.

Thanks to everyone.

Most of the instruments available in the market are good, but due to lack of good maintenance sometimes these meters give problems. So, if you can maintain them well, you can get better results. But be sure you calibrate them before your measurement. Hanna is cheapest in the market.

We have been using Fisher pH meters that have lasted over 20 years. We also have a number of YSI meters that have lasted well over a decade. These meters are used daily in the summer for undergraduate research and during the year for classes. I highly recommend both. I would agree with the maintenance - in particular, dissolved oxygen membranes need routine checking, instruments need to be dried and cleaned at the end of every use, batteries should be checked and replaced periodically, and so on. The biggest issue we found is the pH electrodes which can be fragile and short-lived in the field. We've found Fisher Accumet electrodes are pretty robust.

Dear Raju,

pH, EC, TDS, Salinity, and Temperature – These are generally measured in the field.

These parameters can be determined by the multiparameter tester or pocket tester, very simple device and highly suitable for site work.

This type of device is available from Hach, Eutech, or HANNA . Almost all good. I am using a model of Eutech, the specification of which is attached for your reading. But, I suggest you to compare the specification with other makes for selection.

Best wishes

My experiance are with durable multiparameter taster, as they are simple and suitable for field work.