WaterGuru test results over time

[m100psi]

Hi all,

I found a few threads here comparing WaterGuru results to manual measurements, but all spot checks. I wondered if anyone has significant data on this?

I've had mine a little over a month and compiled some results. If there were consistent offsets between the measurements, even within a limited FC/pH range (as long as it's the acceptable range), WG seems like a great solution. Based on the limited data below, I'm on the fence about keeping it.

Unfortunately, after eliminating all the days where I measured with my Taylor k-2006 prior to WG's measurement (meaning chemicals may have been added between the two measurements), and a few measurements where I was SLAMing, I only have 8 days of solid data. Most of the data indicate more or less predictable offsets (better for FC than pH), but there are a couple exceptions, and I have too few points to know if they can be ignored. I also haven't analyzed how reproducible my manual measurements are, so that could be a factor those days as well.

If anyone else has a correlation with more data, it would be great to see.

Thanks,
Matt

 

[JoyfulNoise]

I think you need more data.

But I will say that it is ALWAYS going to be difficult to compare a pH probe with pH indicators. The processes involved are so different that it’s almost guaranteed there will be an offset.

 

[H-12 1/2 Mike]

I have had WG for about a year and am on the 2nd WG SENSE replacement. I have recently started testing with the Taylor 2006 again because my ph was always high with SENSE (+.5) and the Cl was always low (-4.0). I validated the Cl test with the drop test and strip test. Believe it or not, the strips were only .5 higher than the drop test. I validated the ph by using a ph meter (calibrated), colorimeter test and strip test. I wanted the SENSE to work because of the upcoming TREAT product. I am now changing direction and am now focusing on smoothing out the acid demand process.

 

[m100psi]

I think you need more data.

But I will say that it is ALWAYS going to be difficult to compare a pH probe with pH indicators. The processes involved are so different that it’s almost guaranteed there will be an offset.

I agree about not enough data. I'm sharing what I have, but my hope is that others have more.
A consistent offset would be OK. Since pool chemical criteria are set up assuming indicators (e.g. ideal pH 7.6-7.8), hopefully WaterGuru is putting out indicator-equivalent values.

I have had WG for about a year and am on the 2nd WG SENSE replacement. I have recently started testing with the Taylor 2006 again because my ph was always high with SENSE (+.5) and the Cl was always low (-4.0). I validated the Cl test with the drop test and strip test. Believe it or not, the strips were only .5 higher than the drop test. I validated the ph by using a ph meter (calibrated), colorimeter test and strip test. I wanted the SENSE to work because of the upcoming TREAT product. I am now changing direction and am now focusing on smoothing out the acid demand process.

Wow, you've been seeing +0.5 for pH? That's pretty far off for an ideal range of 0.2. Is it consistently +0.5 or anywhere up to that?
Your results are shifted the same direction as mine, but I haven't seen offsets that large.

 

[H-12 1/2 Mike]

I agree about not enough data. I'm sharing what I have, but my hope is that others have more.
A consistent offset would be OK. Since pool chemical criteria are set up assuming indicators (e.g. ideal pH 7.6-7.8), hopefully WaterGuru is putting out indicator-equivalent values.



Wow, you've been seeing +0.5 for pH? That's pretty far off for an ideal range of 0.2. Is it consistently +0.5 or anywhere up to that?
Your results are shifted the same direction as mine, but I haven't seen offsets that large.

I have included the test results from Wed thru today of this week:

Today: WG = 4.1 FC vs K2006 = 5.6 FC; WG = 7.8 ph vs 7.5 ph(calibrated Apera ph meter PC 60)
Friday: WG = 3.8 FC vs K2006 = 8.6 FC; WG = 7.9 ph vs 7.7 ph
Thurs: WG = 2.3 FC vs K2006 = 4.4 FC; WG = 7.9 ph vs 7.5 ph
Wed: WG = 5.9 FC vs K2006 = 9.0 FC; WG = 8.0 ph vs 7.2 ph

 

[m100psi]

Ok, thanks for the data.