Super low ph

An ngo · Apr 23, 2019

my ph drop from 7.89 to 7.1 after install my uv sterilizer. My ph probe stay in the skimmer chamber, and I just put a pump for my uv in there and water return at the same spot due to small sump. What ph drop so fast like that. It really stable at 7.9 to 8.1 but it happen after I install uv

1Blazer · Apr 23, 2019

Double check your PH probe connection - seems awfully low

redfishbluefish · Apr 23, 2019

It's darn near impossible to have a pH that low. The other possibility is electronic interference.

Entz · Apr 23, 2019

Make sure you didn't end up with small bubbles in the probe from when the UV was turned on and the lines were purging.

An ngo · Apr 23, 2019

I don’t know what happen but it impossible to get that low in 5 minutes. If I unplug the prob, do I need to recalibrate??

Nathan Milender · Apr 23, 2019

My apex probe will do that. Clean it off if there is anything growing on it and if it still does not normalize re-calibrate. I have had fuge critters slime mine up and do all sorts of weird things. Also, if I am negligent on calibration I have had drastic new readings after re calibration. 7.14 is close to plain water, unlikely with bicarbonate buffering. Rock, seashells live and dead, most substrates, all act as buffers and will dissolve as the ph drops to normalize it.

An ngo · Apr 23, 2019

redfishbluefish said:
It's darn near impossible to have a pH that low. The other possibility is electronic interference.

May UV sterilizer suck too much electronic that cause this issue??

redfishbluefish · Apr 23, 2019

I'd either move the pump or move the pH probe and see what pH you have.

sghera64 · Apr 23, 2019

Electrical noise. I do not leave my pH probe in the system any more. I take grab samples. The high voltage in the UV sterilizer is likely causing some sort of EMF field that the probe is picking up.

An ngo · Apr 23, 2019

I found out when i started my pump it made some bubble that stuck into the probe. I just shoke it and it went back like normal

TheU · Jun 2, 2019

sghera64 said:
Electrical noise. I do not leave my pH probe in the system any more. I take grab samples. The high voltage in the UV sterilizer is likely causing some sort of EMF field that the probe is picking up.

A UV sterilizer near a pH/ORP probe can cause electrical interference with the reading. This can be prevented by moving the probe away from the unit or using an all-metal unit that would insulate its signal.