Mike, Have you tested your sensor using fresh city tap water?
Split from this topic. JasonLion
I would be very interested in the results you get with a new ORP sensor.
I have had two HI 98121 pH/ORP/Temp meters from Hanna for over a year (one has an intermittent value on the pH reading) and I really like them for the temp and pH values, but the ORP values have never really correlated with the Cl values I have in the pool.
I also recently purchased one of the epool monitors from Leslie's and that correctly shows cl ppm over or under 2.
I think it would be great to be able to use ORP as a chlorine indicator but the values I'm getting don't make sense.
I just ran a bunch of comparison tests and the results are below. Key takeaway from these tests is that for tap water I am getting the "perfect" > 600 mv whereas with the pool I'm getting much much lower values. Ive seen the 150 mV I measured today even go lower than 100.
I have seen the ORP values affected by static (plastic measuring cup on a dry plastic pool accessories storage box) so I wanted to rule out any container effect, and I checked the cl with different test kits and it's ok (pool is also very clear and clean looking).
Leslie's says I have high phosphates, could that be causing a problem?
I have some minor metal (copper probably) staining on the stairs, could that cause it?
Does the salt from the SWG have any effect?
Any other ideas?
SWG: 3300 ppm salt
TF-100
fc 3 ppm
cc 0.5 ppm
ta 80 ppm
ca 30 ppm
Thermometer temp 32.2 °C
Fresh DPD kit
cl 3 ppm
pH 7.5 ppm
pool orp values (meter held directly in pool)
ORP 150 mV
pH 7.47 pH
temp 32.5 °C
Standing pool water in plastic measuring cup
214 mV
28.3 °C
7.55 pH
Cold tap water in plastic measuring cup
7.16 pH
637 mV
22.7 °C
Cold tap water in glass
7.25 pH
665 mV
24.7 °C
cold tap water in metal saucepan
7.24 pH
688 mV
25.4 °C
Fridge filtered cold water in plastic measuring cup (has only trace cl)
7.3 pH
648 mV
15.7 °C
Gas heated tap water in plastic measuring cup
7.21 pH
645 mV
45.8 °C
Split from this topic. JasonLion
I would be very interested in the results you get with a new ORP sensor.
I have had two HI 98121 pH/ORP/Temp meters from Hanna for over a year (one has an intermittent value on the pH reading) and I really like them for the temp and pH values, but the ORP values have never really correlated with the Cl values I have in the pool.
I also recently purchased one of the epool monitors from Leslie's and that correctly shows cl ppm over or under 2.
I think it would be great to be able to use ORP as a chlorine indicator but the values I'm getting don't make sense.
I just ran a bunch of comparison tests and the results are below. Key takeaway from these tests is that for tap water I am getting the "perfect" > 600 mv whereas with the pool I'm getting much much lower values. Ive seen the 150 mV I measured today even go lower than 100.
I have seen the ORP values affected by static (plastic measuring cup on a dry plastic pool accessories storage box) so I wanted to rule out any container effect, and I checked the cl with different test kits and it's ok (pool is also very clear and clean looking).
Leslie's says I have high phosphates, could that be causing a problem?
I have some minor metal (copper probably) staining on the stairs, could that cause it?
Does the salt from the SWG have any effect?
Any other ideas?
SWG: 3300 ppm salt
TF-100
fc 3 ppm
cc 0.5 ppm
ta 80 ppm
ca 30 ppm
Thermometer temp 32.2 °C
Fresh DPD kit
cl 3 ppm
pH 7.5 ppm
pool orp values (meter held directly in pool)
ORP 150 mV
pH 7.47 pH
temp 32.5 °C
Standing pool water in plastic measuring cup
214 mV
28.3 °C
7.55 pH
Cold tap water in plastic measuring cup
7.16 pH
637 mV
22.7 °C
Cold tap water in glass
7.25 pH
665 mV
24.7 °C
cold tap water in metal saucepan
7.24 pH
688 mV
25.4 °C
Fridge filtered cold water in plastic measuring cup (has only trace cl)
7.3 pH
648 mV
15.7 °C
Gas heated tap water in plastic measuring cup
7.21 pH
645 mV
45.8 °C