What caused my sudden drop in pH???
- Thread starter Pike614
- Start date
MCsaxmaster
New member
My suspicion would be electrical interference giving a spurious reading. However, without more information it's impossible to even begin guessing. If nothing changed in the tank, then the pH couldn't have changed 
Are there any signs of damage to the corals or fish? If not I doubt the readings were accurate. That big of a drop that fast would have hurt something, if not already signs will appear soon. Any extra details that can be givern would help. One thing some people over look is cleaning products that become airborne and any aerosol can cause big drops like that. Any of these used lately near the tank?
Hawk, No cleaning was done, nothing was added except for the grounding probe....corals and fish seem fine, but my pH is always low...It is tough for me to keep it at or above 8.0! Just strange for it to drop off so fast and stay there... I've got it back up to 7.75 and it seems stable, but now I rish high alk. Is there a way to raise the pH without raising the alk?? I did recalibrate the pH probe and got the same readings....
I suspect electrical interference. The probe might alter any interference, but won't change the actual pH. There's no way to raise the pH without raising alkalinity other than by removing carbon dioxide from the water column. I would try using the pH meter on a glass of water, well away from the tank, preferably with a battery-drive meter.
WOW, thanks bertoni! I tested in a pail of water about 5' from the tank and pH went from 7.54 up to 8.25 in about 4 seconds. SO I decided to remove the probe to test it out and sure enough when the grounding probe was removed from the sump, the pH went from 7.54 up to 8.25..... I took out the titanium grounding probe for now until I figure out why it was causing the drop in pH.
The probe turned whatever stray voltage you had in your tank( which at low levels is normal and doesn't move) ) into current(amperage) by giving it a path to ground.This likely caused the interference. It happened to me a while ago. I would not use a probe without a gfci in any case.
MCsaxmaster
New member
To be clear, the probe is not changing the pH of the water. The probe is causing electrical interference in the meter so the meter is not correctly reading the pH of the water. With or without the titanium probe the true pH of the water was (about) 8.25. However, with the probe in place your pH meter was not correctly measuring the pH of the water.
I'm a bit surprised that removing the grounding probe eliminated the interference. I'm concerned that it may reflect some other underlying problem. Simple grounding does not normally cause such a problem for most meters.
What was it grounded to? Is it the same electrical line that the meter is on?
What meter and on AC or battery?
What was it grounded to? Is it the same electrical line that the meter is on?
What meter and on AC or battery?
Yes, the outlet was connected to my RK2 computer, which is connected to my pH probe. I used the titanium probe that has you screw it into the screw on the faceplate of the outlet. All the outlets are GFCI protected. I assume since it is on the same circuit, that caused a feedback loop of some sort...any ideas?
Yes, it may be such a loop, perhaps generated by the computer somehow. Are there any other outlets on a different circuit that you can ground to?
Is the computer/meter grounded with a third prong on its plug?
Is the computer/meter grounded with a third prong on its plug?
My Neptune instructions say to keep it's pH and Temp probes close together, because something about the Temperature probe grounding the pH probe (and ORP).
Does the RK2 have a Temp probe? Maybe it needs to be located closer.
I'd call RK and ask them about it. I called Neptune to ask why the Salinity probe was behaving so erratically and they answered with the electrical interference, and gave some suggestions on how to isolate the probe from it.
Does the RK2 have a Temp probe? Maybe it needs to be located closer.
I'd call RK and ask them about it. I called Neptune to ask why the Salinity probe was behaving so erratically and they answered with the electrical interference, and gave some suggestions on how to isolate the probe from it.
kaskiles,
Yeah, they are about 5" apart actually. I tried moving the pH probe to the other size of my sump (5 feet away) and still got the same readings. I'd call RK but their customer support is extremely poor, only an answering machine at the other end, and it takes days to return phone calls.....seems like the pH reading is fine now though. I might try running an extension cord to another outlet on a different circuit to try and ground it.
Yeah, they are about 5" apart actually. I tried moving the pH probe to the other size of my sump (5 feet away) and still got the same readings. I'd call RK but their customer support is extremely poor, only an answering machine at the other end, and it takes days to return phone calls.....seems like the pH reading is fine now though. I might try running an extension cord to another outlet on a different circuit to try and ground it.
therealfatman
In Memoriam
It should require only a very small wire between the probe and a grounging source to provide a ground against stray voltage. A probe is really not designed to be considered as protection against things like a light falling into your tank. The probes ground wire can be attached to a outlet at a distance or even to a metal water line or a radiant heating systems metal pipe.
Many home grounds are connected to well casings or water main pipes. Wells are in contact with ground water which is an excellent ground, much superior to a 10 foot long ground rod which is often used in modern day construction. Especially if the rod is placed in often dry soil such as under a roof over hang or in a homes crawl space.
Most industrial automation control manafacturers and suppliers are more specific in requiring that control grounds and water grounds be seperate. Most automation control manafacturers such as Omron and Omega, GE, Westinghouse etc. even specify that the circuits feeding controls be on seperate circuits if there are probes used with the controllers or meters. Most Thermo Orion, Oakton and professional level Hanna pH users manuals make mention of this issue. Hanna's cheaper non profeesional meters manuals seem to omit this information.
Aquarium trade manafacturers are known for cutting more corners and being more vague in their instructions, specifications and requirements than the major manafactures and distributers of professinal level controllers and test meters. But when you look at the huge cost differenes between a Thermo Orion meter and a aquarium trade pH meter thing seem more understandable.
The legal liabilities faced by manafacturers and distributers of professional controls and test meters are much larger than those faced by the aquarium trade product manafacturers and distributors. Most products by Thermo Orion, Cole Palmer, Oakton etc. have their manuals gone over by many design engineers (peer reviews and third eye reviews) and typically lawyers before rheir realease for reasons of libailities, this is hardly the case with aquarium trade manafacturers. Actually most designers of professinal equipment have a production departments whose only job is to review contracts, manuals, proposlas and such to protect the design and manafacturing firms in regard to liabilities.
Quality GFCI outlets now are being made where the outlet will not function at all unless there is a proper ground or where the outlet is not fully wired properly. In the past the GFCI aspect would not work if there was not a ground or if the common wireand the load wire were reversed but power would stll be supplied to the outlets. There are still cheap GFCI outlets sold that operate that way.
Even other test probes will often cause interference with each other.
Many home grounds are connected to well casings or water main pipes. Wells are in contact with ground water which is an excellent ground, much superior to a 10 foot long ground rod which is often used in modern day construction. Especially if the rod is placed in often dry soil such as under a roof over hang or in a homes crawl space.
Most industrial automation control manafacturers and suppliers are more specific in requiring that control grounds and water grounds be seperate. Most automation control manafacturers such as Omron and Omega, GE, Westinghouse etc. even specify that the circuits feeding controls be on seperate circuits if there are probes used with the controllers or meters. Most Thermo Orion, Oakton and professional level Hanna pH users manuals make mention of this issue. Hanna's cheaper non profeesional meters manuals seem to omit this information.
Aquarium trade manafacturers are known for cutting more corners and being more vague in their instructions, specifications and requirements than the major manafactures and distributers of professinal level controllers and test meters. But when you look at the huge cost differenes between a Thermo Orion meter and a aquarium trade pH meter thing seem more understandable.
The legal liabilities faced by manafacturers and distributers of professional controls and test meters are much larger than those faced by the aquarium trade product manafacturers and distributors. Most products by Thermo Orion, Cole Palmer, Oakton etc. have their manuals gone over by many design engineers (peer reviews and third eye reviews) and typically lawyers before rheir realease for reasons of libailities, this is hardly the case with aquarium trade manafacturers. Actually most designers of professinal equipment have a production departments whose only job is to review contracts, manuals, proposlas and such to protect the design and manafacturing firms in regard to liabilities.
Quality GFCI outlets now are being made where the outlet will not function at all unless there is a proper ground or where the outlet is not fully wired properly. In the past the GFCI aspect would not work if there was not a ground or if the common wireand the load wire were reversed but power would stll be supplied to the outlets. There are still cheap GFCI outlets sold that operate that way.
Even other test probes will often cause interference with each other.
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Well, I am still concerned about the grounding probe and my pH readings being off. My question is, would it be better to remove the pH probe and havve the tank grounded...or would it be better to have the pH probe in and the tank not grounded at all? With all of the pumps and such in the tank and sump, I am sure there is some stray voltage. Fish do not seem bothered, although I have lost about 4 of my smaller fish, firefish goby, wrasses..ect. Yet my larger tangs are just fine....
ANy suggestions?
ANy suggestions?
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