I put 25 mm water in tube that came with the TF100 and then dumped it into the tube that came with the speedstir and it was very different. Same with the 10mm. My question is which tube should I be using for accurate results.
Tf100 vs speedstir measurements
- Thread starter ennazus
- Start date
That is puzzling. I just repeated your experiment with my TF-100 chlorine tube and the one that came with my speed stir. They were the same. You are taking your measurements before adding the magnetic stir bar correct?
Are both TF tubes (chlorine only and general use) producing different results than the speedstir?
The 10 ml mark on both tubes on the test kit come to the 11.5 mark on the speed stir. The 25 ml mark on the tubes in the test kit are considerably over the 25 ml mark on the speed stir. I think since both the tubes in the kit measure the same its the speed stir one that's off.
- - - Updated - - -
- - - Updated - - -
Yes bot kit tubes measure the same and differ from speedstir.
I just pulled out my Taylor calibrated cylinder and the standard cylinder from the TF-100 kit and my Capp Rhythm Repeater stepper pipette. The bottom of the meniscus was very close to the 10 and 25 ml marks on the Taylor cylinder, whereas the top of the meniscus didn't quite reach the 10 and 25 ml marks on the TF cylinders. I would have to say the Taylor cylinder is more accurate. The precision of the 2 TF cylinders to one another doesn't mean they are accurate.
I just took out my brand new just delivered tf100 kit and new speedstir and did the. 10 mm measure on both tf cylinders and poured into speedstir cylinder [without stirbar] and low and behold 10ml measured in the tf cylinders comes out to over 11.5 on speedstir cylinder!! I also confirmed by measuring out 10mil with a known good measuring pipe.
What gives ..this will throw off these relatively precise tests?? Should I throw out the speed stir cylinder and can I use the tf cylinders on the speed stir?
PS I am awaiting a call back from Wayne in tech support with Taylor to see what's up..I will post back here!
What gives ..this will throw off these relatively precise tests?? Should I throw out the speed stir cylinder and can I use the tf cylinders on the speed stir?
PS I am awaiting a call back from Wayne in tech support with Taylor to see what's up..I will post back here!
Last edited:
If the accuracy of the test results rely on an accurate 10 mL sample of water, you should be using the Taylor cylinder. I spent a pretty penny on that repeating pipette, it should be pretty accurate for anything we do.
My kit is 1 year old & also shows 10 & 11.5 in the two different cylinders. If you look at the black 5 ml line on the TFT cylinder you see it's up higher than it should be. I wouldn't be too concerned about it though, the reading would only be off about 10%. Even at shock levels that's less than 2 ppm for most of us.
I just compared the Taylor cylinder with the TF-100 and got 10 ml with both. If you do notice a difference, please email me at [email protected] so we can fix it. Rebecca
Not sure what you mean exactly we are discussing the measurement markng being off on the speedstir cylinder only. Wayne in tech Support is looking into it He was quite surprised to find out as this was the first call he took on it. I speculated the measurement markings were calculated with a flat bottom erroneously and the dimple on bottom is what has thrown off the measurents.
Again I will post back what happens here to follow up.
Again I will post back what happens here to follow up.
I have the tf100 and I am wondering WHAT IS THE SPEEDSTIR CYLINDER??? I do have the speedstir Thank you
The cylinder that comes with the Taylor SpeedStir is the Taylor 9198. If anything, the measurement on the one from the TF-100 kit is off as the bottom of the meniscus is at the 10 mL line on the Taylor, whereas the top of the meniscus is below the 10 mL on the TF-100 cylinder.
- - - Updated - - -
The SpeedStir cylinder is the clear plastic cylinder that came with the SpeedStir, it has no black lines marking the graduations.
The SpeedStir cylinder is the cylinder that came with the SpeedStir and has the magnetic bar that you drop into it.
- - - Updated - - -
Thanks for posting the discrepancies. I've always used the cylinders from the TF-100 kit for my measuring because they are much easier to read that the SpeedStir cylinder because of the black lines.
- - - Updated - - -
Thanks for posting the discrepancies. I've always used the cylinders from the TF-100 kit for my measuring because they are much easier to read that the SpeedStir cylinder because of the black lines.
When I measured with a known sample size both of my tf100 cylinders were spot on accurate however the speedstir cylinder part#9198 was significantly off.
Cylinders 1 and 2 are the ones found in the TF-100 kit. Cylinders 3 and 4 are found in the SpeedStir and K-1766 kits. 1, 2, and 3 were filled using my Capp Rhythm Repeating Pipette with a 25 mL tip on dispense setting 4 (2,000 uL per press). I depressed the dispense button 5 times, totalling 10,000 uL or 10 mL. Cylinder 4 was filled to an arbitrary amount above 10 mL and the Taylor Sample Sizer was inserted and then gently removed. I lined up all 4 cylinders and took the picture. The results are there for you to interpret.
For information on the Capp repeater: Capp Stepper Pipette. Maintenance free Repetitive Pipette.
Cylinders
Repeater
For information on the Capp repeater: Capp Stepper Pipette. Maintenance free Repetitive Pipette.
Cylinders
Repeater
This was the exact same situation as my cylinders. I tossed all the TF cylinders and only use the calibrated Taylor cylinders along with the Taylor Sample Sizer.