PH Meter and TF-100 Discrepancy

[Enkil810]

Just thought I would get the forums opinion. I ordered the PH meter with my TF-100 kit. I calibrated it per instructions. The meter reads my pool water at 6.9 and my TF100 says more like 8.0. I also checked it with my ColorQ pro which I use for a back up. It says 8.0 Why would the meter read correct in the buffer solution but be completely off in the pool water? Any ideas?

 

[GrandizerGo]

Have you tried leaving the meter in for a while and swish it around a bit? I have one meter that reads a little high initially and then settles down. My second meter is always really high initially until I leave it for a couple of mins.

 

[gregsfc]

Just to make sure...You're not testing with high fc levels are you? Below 7 gives me accurate results with the Taylor kit included in the TF-100; otherwise, If my fc is high, it'll always show 8. I had a Chlorox brand oto/ph tester and it was even more sensitive to high fc levels. Always showed 8.0 if fc was above 4.

 

[TishTash]

<reply to wrong thread>

 

[ajw22]

Cheap pH meters are pretty much junk and get unreliable quickly. They may work for a bit but don’t last long. Their calibration may vary with their battery strength.

 

[scottts]

I should probably give the SpeedStir backlight another try with the FAS/DPD test. After X number of drops, I would think it’s clear, but then immediately after shutting off the light, I noticed it was still pink (as opposed to turning pink over time). Retesting without the light (either on the SpeedStir or manually swirling) confirmed the extra drop. So too bright a light can mask a remaining pink tinge.

I've noticed this as well and I've learned that if you view the sample from the side rather than top-down, you can see the pink better. Once its clear from the side then I don't see any pink after shutting off the light. FWIW.

 

[TishTash]

I've noticed this as well and I've learned that if you view the sample from the side rather than top-down, you can see the pink better. Once its clear from the side then I don't see any pink after shutting off the light. FWIW.

(the post to which this responds should actually (and was moved) to here: )

Discrepancy with recommended Total Alkalinity levels, plus shaking reagents

1) The Recommended Levels calculator mentions 60-80 being optimal for TA. But the instructions for the TF-100 test kit mention 100-120 being preferable for non-SWG pools. I was just wondering about the discrepancy. 2) It’s never mentioned, so is probably unnecessary, but I’ve seen many people...

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