Ph probe for kalk stirrer

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DmnYnkee
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Joined: Mon Aug 11, 2014 6:45 am
Location: Clermont, Florida

Ph probe for kalk stirrer

Post by DmnYnkee »

What is the max Ph reading for ReefAngel. I am wanting to add a second Ph probe for my new Avast K1 Kalk stirrer, and set up notifications when it drops below a specified level so I know it is time to add/replace kalk.

I temporarily placed my tank probe into the stirrer, and it maxed at 10.4, but I am unsure if that is the probe/RA limit, or if my kalk is not saturated. My understanding is that fully saturated kalkwasser should have a Ph of ~12.6 .

Thanks,
Chris
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rimai
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Joined: Fri Mar 18, 2011 6:47 pm

Re: Ph probe for kalk stirrer

Post by rimai »

It should work.
Roberto.
DmnYnkee
Posts: 83
Joined: Mon Aug 11, 2014 6:45 am
Location: Clermont, Florida

Re: Ph probe for kalk stirrer

Post by DmnYnkee »

So I have a brand new ph probe, calibrated with new calibration solution. I have a freshly (within last 48 hours) loaded avast marine kalk stirrer, loaded with new Calcium Hydroxide (kalkwasser mix) from BRS.

If I put the ph probe into the probe holder in the kalk stirrer, I still only get a ph of 10.5 as a max. The probe itself has a range of 0-14.

What am I doing wrong? It should register a ph over 12.
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rimai
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Re: Ph probe for kalk stirrer

Post by rimai »

The constrain on the software is 1.0 and 14.0
https://github.com/reefangel/Libraries/ ... l.cpp#L652
I wonder if there is a hardware limitation.
What is the calibration value you get when it is on such alkaline condition?
Roberto.
DmnYnkee
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Joined: Mon Aug 11, 2014 6:45 am
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Re: Ph probe for kalk stirrer

Post by DmnYnkee »

The calibration values are as follows:

7 - 557
10 - 840

Probe in saturated Kalkwasser jumps quickly to 889, then doesn't fluctuate at all. Almost like 889 is the ceiling.
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DmnYnkee
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Location: Clermont, Florida

Re: Ph probe for kalk stirrer

Post by DmnYnkee »

Would this portion of the libraries have anything to do with it?


/* Constants declare in ReefAngel.h */

const byte ReefAngelClass::PH_MAXIMUM_RANGE[2]={4, 10};

const byte ReefAngelClass::PH_DEFAULT_RANGE[2]={7, 10};
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rimai
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Re: Ph probe for kalk stirrer

Post by rimai »

No. Those are the two points on the calibration that we use.
You can use calibration fluids from pH 4 to pH 10.
Roberto.
DmnYnkee
Posts: 83
Joined: Mon Aug 11, 2014 6:45 am
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Re: Ph probe for kalk stirrer

Post by DmnYnkee »

I am stumped. I have multiple issues going on, and it is affecting my livestock. I can't get ph up and fairly constant which is why I switched back to using kalk (instead of just 2 part), and implemented the stirrer.

I also have 30+ volts of stray voltage in my tank. With all probes and floats unplugged from the top of the RA unit, I am getting a reading of 48v from the serial cable, but tank drops to 15. It doesn't matter if I test the retention screws on the cable, still 48v. I think this stray voltage is leaving the RA unit, and into the tank via the probes and floats. Is my RA bad?
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rimai
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Re: Ph probe for kalk stirrer

Post by rimai »

Did you try the RA by itself without any electrical component powered up and all probes, floats and dimming wires disconnected?
In short, with RA and relay box all by itself.
Roberto.
DmnYnkee
Posts: 83
Joined: Mon Aug 11, 2014 6:45 am
Location: Clermont, Florida

Re: Ph probe for kalk stirrer

Post by DmnYnkee »

Ok, so I shut off all relays, then unplugged all relays, all probes, all floats, dimming, etc. Just the RA head unit plugged into the relay box. Still getting 44-45 volts on the serial cable.

Powering things back up, and noticed something odd. With the ph probe unplugged, I am showing a ph of 8.13. There is nothing connected to the top portion of the main RA at this point? Normal??
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rimai
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Re: Ph probe for kalk stirrer

Post by rimai »

Yes, pH readings without a probe will just float and it will eventually start picking up noise and will either go up or down on it's own.
Do you get correct pH readings when probe is in your sump?
If you had stray voltage, your pH readings would be very wrong when the probe is in your tank.
Roberto.
DmnYnkee
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Joined: Mon Aug 11, 2014 6:45 am
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Re: Ph probe for kalk stirrer

Post by DmnYnkee »

Current ph reading of 7.97 in tank with ground probe plugged in.

With ground probe unplugged I have ~40v in my tank, and ph climbs to 8.02. I unplug the bnc on the Ph probe, and volts drop to 26v in tank. Ph probe by itself in a cup of tank water measures 45v and ph of 8.02.

Now, when the ground probe is plugged in, tank voltage drops to .006v, but Ph drops by about .05, back down to 7.97.

This a probe that has been calibrated in a solution packet that is not grounded, so I would assume that the 45v were coming through there as well, so I am not real confident in the calibration settings.

Combine these issues with the 10.5 max reading on saturated Kalk solution that should be over 12, and you can understand why I am getting frustrated.

Chris
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