Ph Accuracy! Losing my mind

jaime31 · Mar 4, 2023

Hi guys I’m having a dilemma.
I can’t figure out which ph reading to believe and it’s driving me crazy..

I have a Milwaukee ph monitor (mc120) and it reads 7.9-8 and I have the Hanna hand held color meter and that is giving me readings of 8.5

I want to keep it at Atleast 8.2-8.3 so I have some kalkwasser coming in the mail. Now my problem is which one should I believe. I don’t wanna nuke my tank by raising the ph .3 points to 8.8-8.9 and now I’m at a standstill

which one should I believe. The Hanna has a great reputation and the Milwaukee is recently calibrated to the 10/7 ph points.

side notes- I do keep my windows open in the house. I have left for hours with windows wide open and it doesn’t pass 8.0. Also have tons of water agitation including a skimmer running in the sump

thanks guys/girls

Reef. · Mar 4, 2023

You don’t want to be using kalk to raise ph, it’s a good side affect but it’s main job is to replace alk.

The Milwaukee for me, especially as it’s been calibrated.

Court_Appointed_Hypeman · Mar 5, 2023

I have the same issue with PH, probes read 7.90 to 8.16 for the highs and lows, but test kits always put me at 8.3 or 8.4.

I think the probe is probably correct, given how accurately the changes it records in PH corelate with situations that would increase or decrease our homes CO2 levels.

But, also I am familiar with lab grade proves that cost way more than mine that HP vendors have sold a place I worked at, and they would say that "you would be lucky to get an acuracy of .5"

I know pre using probes, anyone testing my tank would think my ph is stellar, and maybe reading the ph of somwthing like sea water for our level of probes is more difficult than reading a standard solution for calibration.

But given this, what I can say is, I have no doubt it's lower than what the probe says given the discrepancy with test kits always being higher, and at the very least the fluctuations I read from my probe are most likely correct and one time saved me from a catastrophic event where ph dipped suddenly due to kids dumping something in the sump.

End of the story for me is, I trust the probe more, but have my doubts its that low, i did switch from dosing only dosing 2 part, to ato kalkwasser, and since that does not add enough alk and calc on its own, 2 part the gap from there. Also just today I made my diy CO2 scrubber into a recirulating one.

Pistondog · Mar 5, 2023

jaime31 said:
Hi guys I’m having a dilemma.
I can’t figure out which ph reading to believe and it’s driving me crazy..

I have a Milwaukee ph monitor (mc120) and it reads 7.9-8 and I have the Hanna hand held color meter and that is giving me readings of 8.5

I want to keep it at Atleast 8.2-8.3 so I have some kalkwasser coming in the mail. Now my problem is which one should I believe. I don’t wanna nuke my tank by raising the ph .3 points to 8.8-8.9 and now I’m at a standstill

which one should I believe. The Hanna has a great reputation and the Milwaukee is recently calibrated to the 10/7 ph points.

side notes- I do keep my windows open in the house. I have left for hours with windows wide open and it doesn’t pass 8.0. Also have tons of water agitation including a skimmer running in the sump

thanks guys/girls

8.5 is high.
Whats in the tank?
Fish only, refugium.
Main source of change in ph is co2. Is the tank in room with people or by itself and gets visited?
Havr you measured in the am before lights on?

jaime31 · Mar 5, 2023

Sorry guys notifications were off for some reason.
But yeah I know 8.5 is pretty much border line..

Testing ph day/night fluctuates .1

The tank is mostly just softies and Euphyllia and some fish.
I don’t have a Refugium and The tank sits in my living room but there aren’t many ppl living here and I also leave the kitchen and living room window open to get great circulation. Not to mention my windows are huge and slide open about 5 feet. I also run a recirculating co2 scrubber..

I forgot to mention that I did a little experiment and mixed salt to 1.026 @ 78 degrees. The bucket says ph should be at 8.3 and that’s exactly what my Milwaukee probe read when dipping it into the freshly mixed water.

That being said I think the probe is right but I would still love to hear from everyone else.

thanks again

gbroadbridge · Mar 5, 2023

jaime31 said:
Hi guys I’m having a dilemma.
I can’t figure out which ph reading to believe and it’s driving me crazy..

I have a Milwaukee ph monitor (mc120) and it reads 7.9-8 and I have the Hanna hand held color meter and that is giving me readings of 8.5

I want to keep it at Atleast 8.2-8.3 so I have some kalkwasser coming in the mail. Now my problem is which one should I believe. I don’t wanna nuke my tank by raising the ph .3 points to 8.8-8.9 and now I’m at a standstill

which one should I believe. The Hanna has a great reputation and the Milwaukee is recently calibrated to the 10/7 ph points.

side notes- I do keep my windows open in the house. I have left for hours with windows wide open and it doesn’t pass 8.0. Also have tons of water agitation including a skimmer running in the sump

thanks guys/girls

They're probably both correct and within their measurement error. I know the Milwaukee is +/- 0.2 at best and if it's a Hanna pen, it's probably +/- 0.5 at best.

Either reading is fine, BTW.

If you want lab grade accuracy you'll have to fork out $3-4k minimum and do 5 point calibration every time you use it.