pH measurments

[jdblake]

I have the new Neptune Apex WiFi controller that comes with a pH probe. Current reading is 7.84. I also use two different chemical tests. One from API, and the other from Red Sea. Both read very close to 8.2. Of course color matching is subjective, but if both are close to the same reading, but different from the probe, which do I use for the tank?

Thanks,

BDJ

 

[bang guy]

If it were me I would first ensure the probe was calibrated correctly. Then I would use the probe knowing it might read a little low. Keeping the PH stable is probably more important that the actual PH reading.

 

[lmforbis]

No probe is accurate without calibration. You need two calibration solutions usually 7 and 10. The calibration needs to be done regularly, at work we do it every day

 

[jdblake]

I did calibrate the probe with both the 7.0 and 10.0 solutions. I have a fish only tank, so I'm not concerned about pH relative to coral, but if the probe is "more" accurate, do I need to be concerned about the lower pH readings?
Should I be adding some buffering compound?
Thanks,

BDJ

 

[bang guy]

Only add "buffering" if your Alkalinity is low. Otherwise it does more harm than good.

 

[lmforbis]

As a research chemist I would always consider a pH meter to be more accurate than a store bought chemical test. I'm not sure if the apex qualifies as a pH meter but I'd still think it was more accurate. I'd agree with Bang that stability is more important.

 

[jdblake]

According to Neptune, the pH probe is lab quality. If this is the correct reading from the probe, is the pH at an acceptable level?

BDJ

 

[lmforbis]

That is a perfectly good pH especially since you have fish only. The probe is lab grade but the rest of it probably isn't but who knows. As long as pH is stable you are fine. Just be sure to calibrate it every week or so, even really high quality lab pH meters drift over time.

 

[geridoc]

According to Neptune, the pH probe is lab quality. If this is the correct reading from the probe, is the pH at an acceptable level?

BDJ

If you paid less than $500 for the Neptune unit then I doubt that it is actually "lab" quality. Take a look at laboratory grade pH meters at Fisher Scientific. that said, the Neptune unit may be perfectly adequate for determining whether your pH is stable, but not reliable for determining the "true" pH.