Thoughts on PH and CO2

[David S]

Hmmmm....
So you think my PH monitor is inaccurate.
I will concede that I have not calibrated the probe in awhile.
I will get back to you, in a few...

So I took a spare PH probe and calibrated to a Pinpoint monitor (don't like the Apex calibration).
It needed minimal adjustment at either 7 or 10. I went for slightly lower.
As of 2pm the Apex probe read 8.4 while the probe attached to the Pinpoint stabilized at 8.15 and is now at 8.17
More...

 

[David S]

I just recalibrated my Apex probe with my Pinpoint.
It was only slightly under in the 10.00 solution but was 7.39 in the 7.00 solution.
I calibrated and it is taking forever to adjust to the tank PH . It started at 9.5 about 15 minutes ago and is still at 8.50.
So my PH was considerably off.
However; consider the following:
My actual PH was about 8.2 at 2pm. From 1 - 5pm I have my lights on at full blast. That causes a large spike in PH. Furthermore, the PH continues to increase as my Led's and T5's start ramping down from 5 - 8 PM.
I will expect the PH to easily exceed 8.4 somewhere between 7 and 8 PM.
In addition, I have added a considerable amount of Soda water the last two days.
I don't think it is unreasonable to claim that the "real" PH in my tank would exceed 8.5 if not for those additions.
I will admit to complacency in not checking the accuracy of the Apex probe this time around, but there have been previous instances where the Apex probe was showing in 8.6 - 8.7 range and those reading were validated by my backup probe with the Pinpoint monitor.
Still more to come..

 

[David S]

I have some comments to make about the PH probes, I have.
One is the Apex probe that came with my Apex controller. The other is ostensibly a Chinese "knock off" I purchased on EBay for 5 bucks.
For any money, I consider the knock off superior.
Reason I didn't incorporate it in my Apex was the wiring is too short.
It didn't take long to calibrate it and when I placed it in the tank water it fully adjusted within 15 minutes.
While the Apex probe didn't take long to calibrate, it is maddeningly insensitive to adjusting to the tank waters PH.
When I first immersed it in the tank water it showed a PH of 9.5. It quickly dropped below 9, but when it reached about 8.5 it seemed to stabilize, which meant the Probe was still reading high, even after calibration!
However, after waiting a bit I recalled this is not the case.
The Apex probe sort of "marks time" (don't ask me why) and it adjusts very slowly
It is 3:25 PM which is about an hour after calibration, yet the PH is still going down (currently 8.35 - 8.36) yet this is the period where my PH should be going up.
Which is what the knock off probe is doing; currently between 8.33 and 8.34.
So I would predict the Apex probe will begin advancing the PH (if it hasn't done so already).
It's sort of like a watch which you move back before it advances.
Unbelievable...
Has anyone had similar experiences with their Apex probe, or do I have a lemon?

 

[J1a]

I am currently using a third party probe on my apex as well. It has been a while ago, but I do remember the apex pH probe gave me some problems with the measure value being exceedingly low (7.6-ish)

 

[David S]

I am currently using a third party probe on my apex as well. It has been a while ago, but I do remember the apex pH probe gave me some problems with the measure value being exceedingly low (7.6-ish)

I take it, though, that you are happy with the probe you replaced it with.
We're you able to calibrate using the Apex (manual or auto?) or did you calibrate with another monitor.
I'm definitely getting a replacement probe. Probably a Pinpoint.

 

[David S]

Ok so I am now officially in "night" mode as the PH is beginning it's descent.
I had a confirmed PH high of 8.5 in my backup probe that is connected to the Pinpoint monitor. However, it probably was slightly higher as it hadn't quite reached the peak period.
After recalibrating the Apex it showed a high of 8.58.
An average of the two of 8.54 is IMO too high.
I've never been happy with the Apex PH probe so once and for all, I'll be buying a Pinpoint probe on BF.
I just hope it's the probe that's messed up and not the calibration process.
So I will continue to use soda water whenever the PH exceeds 8.5.
I also like the fact that it seems to lessen the drop at night.

 

[J1a]

I take it, though, that you are happy with the probe you replaced it with.
We're you able to calibrate using the Apex (manual or auto?) or did you calibrate with another monitor.
I'm definitely getting a replacement probe. Probably a Pinpoint.

Yes, I'm extremely happy with the replacement probe. I use manual calibration on apex for both the original apex and the replacement.

In any case, I am not that concerned with the exact 0.01pH or anything. I use it mainly to tune my CO2 scrubber.

 

[David S]

Randy
One issue I know I will have

Yes, I'm extremely happy with the replacement probe. I use manual calibration on apex for both the original apex and the replacement.

In any case, I am not that concerned with the exact 0.01pH or anything. I use it mainly to tune my CO2 scrubber.

Ok

 

[David S]

Randy
One issue I know I will have when adding seltzer is the salinity will drop.
This is compounded by the fact that I already use Kalkwasser in my make-up water.
What potential issues if I added some salt to the soda water?

 

[J1a]

Could it be that you have overly high pH because you dosed too much kalkwasser?

 

[David S]

Could it be that you have overly high pH because you dosed too much kalkwasser?

I don't think so, for two reasons:
1. I am not dosing Kalk from 11am - 7pm and the PH really takes off during that period.
2. While I am dosing the Kalk at night, it is not enough to prevent a sizeable drop in PH.

 

[David S]

An update on my Reef:
I have not added soda water the last two days.
Wednesday the PH hit a high of 8.51 (decided not to dose) and yesterday it hit a high of 8.49.
In earlier posts I expressed my skepticism about the accuracy of the Neptune PH probe.
As a result, I bought a Pinpoint earlier today. But rather than using it as a replacement, I'll keep it as a spare.
That is because I did some tests, where I calibrated my current backup using the Pinpoint monitor while calibrating the Neptune probe in Fusion (auto mode) at 5pm on Wednesday.
As usual the PH readings with the Pinpoint monitor normalized within 15 minutes and the Neptune was way high (over 12 after calibrating). Even after a couple of hours, the reading was too high.
But approaching midnight the readings from both probes were within 0.02 of each.
Since then, I've been monitoring both probes simultaneously and they have not deviated from each other by more than +/- 0.03.
As of 1:30 PM today they both measured 8.21.
So it seems that the Neptune PH probe takes at least 6 hours to adjust.
At least mine does. I don't know if anybody can corroborate or disavow this, based on their own experience.

 

[X-37B]

Just some info.
15 minutes seems like a long time to stabilize.
I do not run apex.
I do run the apex probe on my Milwaukee unit and it is reads ph very fast.
I have an old Hanna ph/orp unit that takes a few minutes to stabilize but both units read the same.

 

[David S]

Actually the 15 minute stabilization period is for the Pinpoint monitor and that's "good".
The Apex unit takes several hours to stabilize.
So when I receive the new probe, next week, and it too takes hours to settle after calibration, I'll know it's something in the Apex software.
However, if it settles quickly, I would assume the problem was with the probe.

 

[las]

An update on my Reef:
I have not added soda water the last two days.
Wednesday the PH hit a high of 8.51 (decided not to dose) and yesterday it hit a high of 8.49.
In earlier posts I expressed my skepticism about the accuracy of the Neptune PH probe.
As a result, I bought a Pinpoint earlier today. But rather than using it as a replacement, I'll keep it as a spare.
That is because I did some tests, where I calibrated my current backup using the Pinpoint monitor while calibrating the Neptune probe in Fusion (auto mode) at 5pm on Wednesday.
As usual the PH readings with the Pinpoint monitor normalized within 15 minutes and the Neptune was way high (over 12 after calibrating). Even after a couple of hours, the reading was too high.
But approaching midnight the readings from both probes were within 0.02 of each.
Since then, I've been monitoring both probes simultaneously and they have not deviated from each other by more than +/- 0.03.
As of 1:30 PM today they both measured 8.21.
So it seems that the Neptune PH probe takes at least 6 hours to adjust.
At least mine does. I don't know if anybody can corroborate or disavow this, based on their own experience.

I couldnt pick a better ph range for a whole day than 8.3 to 8.5.

 

[David S]

I couldnt pick a better ph range for a whole day than 8.3 to 8.5.

Unfortunately, it didn't stop at 8.3
It went to 8.08.
Still, that's normal for my system.
It's when it gets in the 8.6 - 8.7 range that it could be problematic.

 

[las]

I see. I wouldnt want a ph swing much more than .2 either. Hope you find the results you are after. Maybe you could put an algae scrubber on your system that you can kick on when PH hits 8.3 and kick off when it hits 8.5?

 

[David S]

I do grow red ogo. (Gracilaria) at night. But it has not helped at all

 

[David S]

Ok so I got a Pinpoint monitor a few minutes ago and calibrated with my Apex.
Upon calibration the PH reading settled almost immediately. It had been 8.51 with the Neptune PH probe. The Pinpoint had an initial 8.56 reading, but within a few minutes normalized to the same reading of 8.51.
Currently up to 8.53.
So I then calibrated the Pinpoint Probe to the Pinpoint monitor and I got an identical reading of 8.53.
Until I got the Pinpoint Ph probe I did not know which PH probe to believe. The 5 dollar PH probe was running 0.02 - 0.05 lower than the Neptune probe.
The Pinpoint results pretty much validate the higher PH reading in the tank.
BTW tried dosing soda water but the CO2 evaporated .
Gotta hit Trader Joe's tomorrow.