Summary for pH controller issue Discussion
pH controller issue for aquarium: Michal describes a 3-month-old planted JUWEL Rio 240 tank with KH 7, GH 10, EI fertilizing, and a CO2Art CO2 system with a pH controller. After calibrating it, he first ran the CO2 on a timer at night, then switched to 24-hour controller use because of day/night pH swings. He noticed an abrupt displayed change from about 6.8.4 to 7.0.4 when the lights turned on, and a similar immediate drop when they turned off, and CO2Art said it might be normal. The only answer, from a site moderator, says the forum is mainly about metal finishing, but notes that pH controllers can be sensitive to electronic noise because they read millivolt signals. The advice is to keep probe wiring away from AC wiring and cross it at right angles if possible, and consider shielding around AC wiring. The responder also suggests an aquarium expert may be needed for a definitive answer.
March 30, 2016
ACRONYMS:
GH = General Hardness
KH = Carbonate Hardness
ferts = fertilizer
EI = Estimative Index method
Q. Hi guys this is my first thread
First of all English is not my first language so I will do my best to keep my grammar on best possible level.
Now let’s start with the problem:
Aquarium – JUWEL rio 240
Planted tank – 3 months old
KH – 7
GH – 10
ferts – EI
I have recently purchased a CO2 system set from the CO2art which is very respectable company. I also got the PH controller in the box as a part of the CO2 set. After I calibrated carefully as per instructions and connected the PH controller to the timer so the CO2 was turned off during the night as I know that plants doesn’t really need the gas to be injected during the night time. But then I realized that there is some PH swing going on between the night and day so I decided to use the PH controller 24 hours without the timer. I set the PH on the controller for minimum 6.8.4 and maximum around 6.9.0 so if the PH fall down to 6.8.0 during the night then PH controller will turn on the solenoid to stop the gas injecting to the aquarium and if the PH goes higher up to 6.9.0 then it will set the solenoid to inject the gas to keep the PH on similar level.
Anyway soon as I started using the PH controller for 24 hours I realized something weird when the lights switch on and off in the aquarium.
So in the morning my ph controller display show ph 6.8.4 and when the light switch on the ph controller display shows a very quick PH swing from 6.8.4 to 7.0.4 !!! this is 0.2.0 more in about one second ! The same thing happen when the light switches off then ph on the controller display changes immediately from 6.9.4 or from 7.0.0 down to 6.8.4 !
I contacted with the CO2art and they told me that it could be just normal thing but I don’t believe that. Do you guys have some similar experience with the PH controller when light switch on or off ?
Michal Sendrak
hobbyist – Dublin Ireland
March 2016
A. Hi Michal. This site focuses on metal finishing which, like many other fields, can involve pH control — but I know nothing about new technology CO2-injected aquariums beyond what I googled and read in 5 minutes :-)
Yes, pH measurement involves transmitting millivolt signals from the sensor to the amplifier/control circuits, so pH controllers can be quite sensitive to electronic noise. To the extent possible, keep pH probe wiring away from AC wiring and perpendicular to it. It may be necessary to add some sort of ground shield around the AC wiring. Beyond that, we can both hope that an aquarium expert sees your posting and stops in to help, but it may not be likely :-(
Luck and Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.