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Marine Pinpoint Calibration questions

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I have to buy some calibration solution, and for ease would like to buy a calibration liquid instead of making it myself.


Should I buy ph 4 and calibrate to that, or buy ph 7 and calibrate for that?  Which would give me more accurate results for my tank(s)?


Also, this one says 7.0ph at 25c .  How am I supposed to get it that cool, or is there a temp stable one I should get instead?  Help?

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Yes, it's two points calibration. so you need two reference solution.

for freshwater, choose pH4 and pH7. for saltwater, choose pH7 and pH10.


You would need three cups for the process.(for freshwater)

1, pH 4

2, tap water, you can use RO water too.

3. pH 7


After rinse probe.

1, put it in pH4 solution, and wait for couple minutes, let reading stable, then adjust the pH4 trim

2, rinse probe in tap water

3, put it in pH7 solution, and wait for couple minutes, let reading stable, then adjust the pH7 trim

4, rinse probe in tap water


repeat step 1 to 4, until both pH4 and pH7 reading is accurate without adjust the trim. Done.


Use solution at room temp. there is a table on the bag to tell you the accurate value based on temperature. I won't buy the bottle, I discard the solution after calibration.



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James has it all listed for you, I did purchase a 4,7,11 liquid set much easier for me than mixing the powders.  I got a liter of each fluid so I will have plenty for multiple calibrations. The set was pretty cheap I think $15.

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I'm reasonably certain the brand doesn't matter.

Definitely get some little cups to use. I almost spilled all of the solution the probe came with, as I realized at the last second that putting it into a shallow food dish was not going to work.

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How long does the probe last on this unit? I ask because I use a ph meter daily at work and over time the probe loses its efficiency. So we have to buy a new probe every so often.


It's about a year.

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