My tank is extremely stable and has been running solidly with no problems for about 2 years now but I noticed that my pH has always seemed to be consistently high:

pH Stats

All other readings are as the community would expect, virtually no ammonia, nitrites, nitrates, phosphates, calcium is good, salinity good, regular water changes.

It just seems odd ...

I wonder if this is the reason that in the past I haven't been able to put certain forms of life in the tank.

I had issues with anemones mostly (3 died in the past causing serious havoc when they did).

Should I be concerned about this?

  • are you dosing kalk? what's the ph of your mix for water changes and how much?
    – Mark S
    Oct 15, 2014 at 20:24
  • nope and i think the ph goes in at 8.2 ... although i havent tested it so it could be that the salt mix is registering at this high level and that actually theres an issue in how the seneye sensor works
    – War
    Oct 15, 2014 at 22:22
  • sounds like a calibration might be in order
    – Mark S
    Oct 16, 2014 at 2:10

1 Answer 1


No need to worry. pH is affected by an almost immeasurable amount of factors. Something as benign as turning on a ceiling fan can measurably alter the pH on a tank due to CO2 concentration in the air or degassing in the tank.

Just an example on my main reef tank:

enter image description here

On the 21st, we turned the air conditioner back on and you can see the average pH go up just from that.

I would definitely re-calibrate the probe if it hasn't been in a year or two.

But realistically, pH is more of a long distance measurement and isn't extremely important in day to day care. The exception is if you were directly dosing CO2 for a planted tank or a calcium reactor in which you would want to keep close track of ph so you don't mess up the tank.

  • weird how "unstable" your ph is compared to mine ... i would be freaking out if my tank was bouncing about like that but you have a point, with the ph being so predictable and stable it's less important I guess.
    – War
    Oct 16, 2014 at 21:56
  • It's actually not as bad as it looks. I forgot to get the scale on there when I took a screenshot, but it generally fluctuates between 7.7 and 7.9. Ph is going up during the day due to algae consuming CO2 when the lights are on. Goes down at night when it consumers oxygen.
    – Jestep
    Oct 17, 2014 at 13:46
  • Ah that makes sense ... mine looks relatively flat but is essentially doing the same thing around 8.4 to 8.6
    – War
    Oct 17, 2014 at 14:48

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