problem with pH reading

Bogdan · Post by **Bogdan** » Thu Sep 13, 2012 7:34 pm

After about a month of working correctly, yesterday the pH reading dropped to ~2 and then raised to ~5. I recalibrated the probe. The reading for pH7 and pH10 went down respectively from 554 to 457 and from 832 to 741. When I put the probe back to the tank or sump it still reads ~5. When I test this probe in a cup with the water from the tank it shows 8.11 which is about right. So i thought voltage leaking in the tank. I tried to unplug every item one by one with no results, the reading remained in the ~5 range. Tested it in cup again and it shows over 8 which is correct. What could be the reason of the false reading when the prob is in the tank/sump? Also keep in mind that it just happened yesterday.

rimai · Post by **rimai** » Thu Sep 13, 2012 7:50 pm

Can you check you float switches?

Bogdan · Post by **Bogdan** » Thu Sep 13, 2012 8:00 pm

That was it, when ATO switch is unplugged pH reading goes back to normal.

Bogdan · Post by **Bogdan** » Thu Sep 13, 2012 9:24 pm

Is there a way to fix this bad switch or I need to order a new one?

rimai · Post by **rimai** » Thu Sep 13, 2012 9:33 pm

Was it the exposed leads that was touching the water or the float itself that causes the issue?

Bogdan · Post by **Bogdan** » Thu Sep 13, 2012 10:04 pm

The leads are outside the sump and I isolated them with electrical tape, it must be the floating part of the switch.

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