For everybody that uses the Pocket Colorimeter by HACH, what is your typical reading? I'm curious if I'm too close to the 0.10 maximum level for total chlorine. My readings range from 0.05 to 0.09. Sometimes I reaach 0.10 and I have to do the free chlorine reading in order to get under the limit.

Nobody has any experiences with their pocket colorimeter and the range in readings they are getting?

We were using the colorimeter for our post carbons, but now we use the RPC strip, and we use the colorimeter for just the RO water once a day. When we were using it, we were getting results between 0.5 and 0.09. They also were sometimes getting 0.12-0.16 and would have to retest. When they wouls retest it would be within range. However we did rebed 3 times. We checked our water and had some interferance problems which is why we just switched to the RPC for the post carbons. Now we are getting 0.02-0.04 with the strips and 0.01 at the RO.

We use the HACH pocket colorimeter and routinely get 0.01-0.05
Any deviations in the past have been related to:
Not using same vial to test with as to zero with.
Cloudy glass vial (cleaned with isopropyl alcohol)
Scratched vials
Dirty sensor in colorimeter

<jdbiomed>,are you a fresenius unit.why would you wanna try to get UNDER the limit by trying another method.checking for Total Chlorine,0.10 is unacceptable.when was your carbon changed last? is your town inducing more chlorine into town water to cure a bacteria problem? make sure you dont having any interfering substances in water,giving you a higher reading on your Hach meter.if unsure,call Hach and order an interference solution kit and follow the directions.

MJPC,

Why is checking for total chlorine at 0.1ppm unacceptable?

I believe mjpc means that .1ppm is an unacceptable result as far as dialyzing and trying to find a different test to get a lower number is not the right thing to do.

Mark, I believe that they were referring to checking for Free Chlorine to get an exceptable result is not allowed. You have to check the Total Chlorine post carbon and the Total Chlorine has to be <0.10. You can't just check the Free chlorine to make your test pass!

Thanks Bo for correcting my typo;thats why you get paid the BIGGGGG bucks!!!!

I think a clarification is called for here. Total Chlorine is an acceptable limit to check, if the level is below 0.10ppm. In the event the Total Chlorine is greater than 0.10, or exactly 0.10 ppm, the Free Chlorine must be checked. Whatever the result of the Free Chlorine is, must be subtracted from the Total Chlorine result. Note: AAMI standards are <0.10 Chloramine and <0.50ppm Free Chlorine. Therefore if the test for Total Chlorine is >0.10 you are correct to say it is above the "normal" parameter for chlorine. However, it doesn't mean it is above the AAMI limit, when you are considering the 2 main constituents of "Total Chlrorine", which is Chloramine (<0.10ppm) and Free Chlorine (<0.50ppm), these values must be determined in the event of a spike in Total Chlorine. The difference between Total chlorine and free chlorine is the chloramine level. I hope this helps.

What happens when you get a free chlorine level greater than the total chlorine level? Yes I'm familiar with the variables with vials, dirty sensors etc. but if you do not like the results you test again to get a better end result. I think somehing so important should not be full of so many variables and variations.

as using the Pinwheel for a long time then switched to the awfully dreaded so called great colorimeter ( which is ten time less accurate ) Now looking into RPC test strip now ....

Main concern of the colorimeter is it very inaccurate first reading would be .06 5 min later .01 5 min later .09


And yes vial is not dirty - scratched - or other
it is the colorimeter that sucks !!!!!


for those how swear by the colorimeter I hope nothing bad happens in your clinics

By definition, it isnt possible to have a Total Chlorine reading greater then the Free Chlorine reading. Perhaps because the AAMI limit for free chlorine is 0.50ppm, as opposed to a 0.10ppm AAMI limit for chloramine, the notion that a high Free chlorine reading might produce a "negative" reading, is impossible mathematically.

I have been having issues with my colorimiters.(in all 4 units)We have been getting completely inaccurate readings. I have also rebedded waaay too many times. We have found out that it is confirmed by an outside water testing facility that our incoming water contains Maganese, which is known to skew chlorine readings. We have been doing comparison testing with the RPC strips and at the same time, a test with the colorimeter.5 tests throughout the day.The RPC test strips are proving far more accurate, easier to use, and more user friendly for the non-technicial staff that uses them.

(Concerned)

You must take your reading between 3 Min and 6 Min to get the reading. After 6 min the reading will go up and up and up. Read your manual.