Conductivity problems

[BeanAnimal]

A bit confused here.
I have calibrated the conductivity probe half a dozen times. It is nowhere close to 2 refractometers or a Hanna digital all of which are calibrated with 2 different commercial solutions.

What I don't get is that the live reading and those recorded on the chart differ greatly.

This is the LIVE reading today and the chart reading for the same period
Live 1.0173
Chart 1.0219 (closer to refractometers)
There is no Density offset (0.000) saved on the setting page. Why are the LIVE readings and the cart not the same?

Also no clue why/how that huge dip was recorded.

 

[KStatefan]

I sure you already know this but it has come up before with other users GHL uses density and not specific gravity

 

[BeanAnimal]

I sure you already know this but it has come up before with other users GHL uses density and not specific gravity

I am not so much looking for a reason as to WHY the probe is not accurate (I get that there are issues with temperature an density conversion to SG) but why are the chart history and live readings not the same?

 

[BeanAnimal]

Also - it appears that the chart is at least an hour off
12:09PM on PC and P4
Charting set to 60 mins

But there is no reading for 11:45 AM so the charting is missing that entry, indicating that it is at least an hour off.

I have had this think less than 4 days and hate to think that I found a bug or problem and hope that I am simply missing something very simple.

@Vinny@GHLUSA can you please offer some insight?

 

[Lasse]

There is two questions here.

The first - you get no stable readings - you can compare with my readings from my probe (+4 years old) - I use PSU bur nether the less

I had readings like yours before but I place the electrode in the sump in that way that my siphon tube is direct aimed to the opening of the electrode. It needs a high water velocity to give a steady reading. If it is too low, bubbles form on the electrodes that prevent the reading - they build up - disappear and affect the reading

The measurements is not uploaded direct - they seems to be batch uploaded with several hours between. I have sample period of 5 min. Time just now

Chart for the moment - last uploaded 18:00

But you also need to have the right offset here (I am +1 hour GM

Sincerely Lasse

 

[BeanAnimal]

Thank you for the response Lasse -

I will try to move the probe to a higher flow area - right now it is in the coast-to-coast overflow.
I was viewing data from the local web IP - so assumed it was in real-time.
I still don't understand the difference in reporting data and live data, but maybe it is skewed by time.

I just got two data points uploaded back to back and there is another dip - so will look into the air bubble issue.

 

[Lasse]

Of some reasons - I suspect that you have a siphon tube down to your sump . Place it in the outlet of that tube

Sincerely Lasse

 

[BeanAnimal]

@Lasse

Still in overflow - things appear to be a bit more stable. I ordered the measurement cell and will plumb it inline when it gets here. My sump is DIY acrylic with a Eurobrace and it makes adding probes hard.

 

[BeanAnimal]

Also got KH director setup and readings are stable at this point. Only a few readings so far.