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Lightsluvr
01/13/2010, 08:10 PM
I was one of the early Apex users - have had mine up and running since August.

The pH in my 500G system has run solid as a rock for months. It peaks at 8.4 when lights have been running and gradually falls to 8.15 just before the lights come back on the next day. Never varies.

Suddenly, the Apex has started giving bizarre readings. It might read as low as 6.43 and up over 9.0 in as little as a hour or less. I cleaned the probe and tried placing it in different parts of the tank or sump, but it doesn't seem to matter. About the time I really get frustrated, it starts reading correctly again, and then just as quickly it goes nuts.

Any suggestions on why this is happening?

My next step will be to calibrate the probe, but I am thinking calibration is not the cause, but rather some type of interference or software glitch?

Thoughts?

LL

tamu
01/13/2010, 09:20 PM
Is it a quick spike that goes back up/down to normal in a minute or two, or does it take hour(s) to go back down?

Lightsluvr
01/14/2010, 04:31 AM
I received a PM about my Apex setup:

How many EB8s do you run? The reason I ask, I see spikes all the time, but when I run the system off one EB8 only the probe runs flawless. If there is any way to try it, I would love to see what your results are. You could just have a bad probe though.

My probe runs perfect during the day, but goes nuts at night with constant spikes. Mine are always up, never down.

Reply:

I am running (2) EB8s. But I have been running two for quite a while. The pH spikes just started a week or so ago.

LL

Lightsluvr
01/14/2010, 06:06 AM
Is it a quick spike that goes back up/down to normal in a minute or two, or does it take hour(s) to go back down?

It can do both. I have seen it change from 8.25 (normal) to 7.90 in one refresh of the Apex.

Here is the graph of pH since midnight - note the spikes... obviously something is going on.

http://i242.photobucket.com/albums/ff125/lightsluvr/pH0114.jpg

Any other thoughts about possible interference - suggestions about probe location or shielding?

LL

tamu
01/14/2010, 06:18 AM
Try running off only 1 EB8 for a night.

swearint
01/14/2010, 09:28 AM
Take a sample of tank water in a cup and place the probe in it for an hour or so and see if it continues to behave erratically. If it does, I would suspect the probe. If it does not, then you may have a pump or other piece of equipment that is leaking current and needs to be replaced. You can disconnect equipment one at a time until you isolate the problem.

Todd

kenargo
01/14/2010, 10:03 AM
Many great suggestions above...

I would add:

It almost looks like a pattern from dosing or top-off. It could be errant equipment (heater???).

Try comparing the outlet log against the times the PH drops and see if there is a pattern...

Lightsluvr
01/14/2010, 03:49 PM
Thanks for the tips. I'll start with the easiest first. I will place the probe in a cup of tank water to see if the pH settles down.

LL

Lightsluvr
01/14/2010, 04:15 PM
Many great suggestions above...

I would add:

It almost looks like a pattern from dosing or top-off. It could be errant equipment (heater???).

Try comparing the outlet log against the times the PH drops and see if there is a pattern...

The Top-off pump has been shut off for several days while I await a replacement pump from Tunze. It can't be the Osmolator.

The heaters ran for an hour or two a day during our recent big freeze. However, they haven't turned on in the past two days. So it can't be the heaters.

LL

Lightsluvr
01/14/2010, 04:22 PM
Take a sample of tank water in a cup and place the probe in it for an hour or so and see if it continues to behave erratically. If it does, I would suspect the probe. If it does not, then you may have a pump or other piece of equipment that is leaking current and needs to be replaced. You can disconnect equipment one at a time until you isolate the problem.

Todd

Thanks Todd.

Want to hear something bizarre? I took a clean plastic glass and filled it with tank water. I removed the pH probe from the sump and placed it in the cup of tank water. The pH reading on the Apex immediately fell to 2.60 and then soared to 10.03 (!!!)

I swished the probe around in the cup and it made no difference. It remained at 10.3. I measured the cup's pH with a handheld digital pH meter and it read 8.38.

After scratching my head about these results, I placed the Apex probe in the tank's overflow, where it had resided since the controller was set up. Immediately, the Apex read 8.38 (!) A half hour later, it is holding at 8.4, which is the pH I expect to see on this tank after the lights have been burning for several hours...

Go figure. Probe heal thyself?? I doubt it.

LL

Lightsluvr
01/14/2010, 08:25 PM
Well, I haven't done anything to the probe and now ithe Apex is reading 7.27. :hammer:

No...make that 7.23 (in just 5 minutes) :thumbdown

LL

kenargo
01/14/2010, 08:31 PM
Well, I haven't done anything to the probe and now ithe Apex is reading 7.27. :hammer:

No...make that 7.23 (in just 5 minutes) :thumbdown

LL


It's starting to sound like a bad probe...

aquamanic
01/15/2010, 06:42 AM
X2. I'd call Neptune. Probe should last more than 5 months. Should be under warranty anyway.

Lightsluvr
01/15/2010, 07:29 AM
I have two pH probes. The second one is currently in my CA reactor. I will be taking down the reactor this weekend and will place the second probe in the tank. If both probes give wacky readings, I'll know for sure it's not a bad probe and will have to look elsewhere for stray voltages, etc.

LL

Lightsluvr
01/18/2010, 09:34 AM
When I took my CA reactor off line, the erratic pH readings went away! I don't know if it was the Rio feed pump or the Mag 7 circulating pump - or some other anomaly...but now both pH probes are providing steady (though not equal) pH readings.

You can see in the seven day graph below where the correction occurred: Top graph is the DT probe - note how the pH readings smoothed out when the CA reactor was disconnected. The bottom graph was the old reactor probe - you can see where the pH jumped when it was placed in the sump.

http://i242.photobucket.com/albums/ff125/lightsluvr/pH0118.jpg

At this moment, the original probe, located in the DT overflow, reads 8.24. The probe that was in the reactor is now located in the sump and reads 8.33.

They have tracked steadily over the past 48 hours without any glitches... they're just not reading the same...

I will calibrate the probes this weekend and see the if they start providing the same readings...

LL

P.S. - Tank pH is slightly higher now that the CA reactor is gone. I suspect the change is because CO2 is no longer being injected.

aquamanic
01/18/2010, 12:09 PM
This is a question, I don't know but is it realistic to expect your DT and sump readings to ever be the same? I mean, the sump has your skimmer, perhaps a fuge, highly agitated water, etc. I would expect them to be different - close perhaps but not the same.

Lightsluvr
01/18/2010, 01:50 PM
This is a question, I don't know but is it realistic to expect your DT and sump readings to ever be the same? I mean, the sump has your skimmer, perhaps a fuge, highly agitated water, etc. I would expect them to be different - close perhaps but not the same.

That's a good question, Alan - maybe someone can chime in... certainly the rate of flow is greater in the DT's 36" external overflow than it is in the return chamber of the 95G sump... I note that the difference in pH readings is consistently .7 and .8 - with the overflow being lower than the sump...

LL

Lightsluvr
01/18/2010, 03:42 PM
Well, I spoke too soon... that original pH probe has gone bonkers again... now while the probe in the sump is holding steady at 8.4 while problem probe has plummeted to 7.4 and is wavering between there and 7.7!

Back to the bad probe likelihood? Maybe I'll give Curt a call if this continues...

LL

Lightsluvr
01/18/2010, 03:56 PM
That's a good question, Alan - maybe someone can chime in... certainly the rate of flow is greater in the DT's 36" external overflow than it is in the return chamber of the 95G sump... I note that the difference in pH readings is consistently .7 and .8 - with the overflow being lower than the sump...

LL

Of course the difference was actually .07 and .08 - NOT .7 - .8 :hmm5:

The errant probe has now jumped to 8.10...

Arrrgh.

LL

cohl87
01/18/2010, 04:32 PM
I am currently experiencing the same problem with my ph probe, I got my apex when they first came out, and had no issues with my ph probe until I recently did the software update. I get erratic readings like 8.5 all the way to 7.5 in just a few minutes, I have calibrated it many times, and today I just received a new probe thinking my old one was bad, but the new one still shows crazy readings. so i am anxious to hear what your problem is, hopefully it will fix mine to0.

kenargo
01/18/2010, 04:47 PM
Suggest contacting Neptune or send email to [email protected]; no sense in guessing what is going on when they have some diagnostics that can point you to the right location.

chatyak
08/06/2011, 09:16 PM
Was there a solution to this? I am having the same problem. From 8.3 to 9.8 in just a couple minutes.

Specialtang
08/06/2011, 11:12 PM
had the same issue when I added more than two EB8 or just one more EB4

Send it back to Neptune Systems

Lightsluvr
08/07/2011, 12:42 PM
I should have come back and posted an update on this old thread.

After ordering two new pH probes, I decided to re-route the probe cables. It turns out that probe readings can be adversely influenced if they are too close to flourescent bulbs (like T5, etc.)

When I routed them as far away from the bulbs as possible, the readings stabilized.

I calibrated both probes and they read within a tenth of a point of each other. I have two brand new pH probes, in the box! :worried:

LL