Automated Alkalinity Measurement

[rygh]

So as part of designing my water-exchange system, I was thinking about Alk, and
that it might be possible to integrate a simple ALK measurement device.
There were others interested, so here it is.

This is NOT something that does fancy automated titration, and gives you a dKH number.
(Although I do have some ideas on that also)
This is simpler. It really just tells you if your ALK has deviated much from a set level.
But that is what you really need most of the time anyway.

And a BIG caveat: I have not built and tested it yet, and might never do it. It may not work at all.

The design is attached as a PDF.

Water exchange thread here:
http://www.bareefers.org/forum/threads/over-designed-salt-water-exchange-system.16510/

 

[rygh]

Comments welcome, especially if you see a problem.

 

[tygunn]

I'm definitely interested in this. So have you figured out the ranges of error at the various stages to get an idea of roughly how close the number you get will be to actual?

 

[rygh]

I'm definitely interested in this. So have you figured out the ranges of error at the various stages to get an idea of roughly how close the number you get will be to actual?

I have not experimented yet, no.
Main error causes:

* PH probe drift
Minimal, since we can compensate by using the first measurement.

* Inconsistency in Acid solution
Might need to shake that occasionally.

* Inconsistency in amount of Acid solution added
Peristaltic pumps are decent, but far from exact.

* CO2 effects
Not sure about that one.

* Non-linear PH/Alk curves
If we are not in a fairly and steep part of the curve, a small error can throw
the measurement off quite a bit.

I have a lot of things ahead of this in my to-do list, so it will be a while.

 

[Ranjib Dey]

Resurrecting this thread :0)
@rygh Is this still operational?

 

[rygh]

Resurrecting this thread :0)
@rygh Is this still operational?

Never really got it going.

Did a few measurements and things, then work+family got in the way.
I do think it would work for "tracking" Alk, and telling me if it drifts, but not something
good enough to actually measure the value.

And now it looks like real measurement tools are finally making it to market.

But another recent thread on R2R did get me interested a bit again, so who knows.
I am wondering if it is a coincidence that you are resurrecting this.

 

[scuzy]

Just get one of the already avail solutuon


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[Ranjib Dey]

No its not coincidence. I came here chasing down that thread :0-)

I had pondered about a more generic version of that, semi-automatic titration system. I'll get to it sometime in future. The r2r thread is important as the author has mentioned making it opensource, if that happens, whatever comes out of that project can be useful.

 

[rygh]

Just get one of the already avail solutuon


Sent from my iPhone using Tapatalk Pro

Or send water out every couple months to be Triton tested.
At $25 per test, 4 times per year, that is 10 years worth for the same $1000 as a tester.
And you get all sorts of results, not just Alk.

A bit of a different application though.

 

[scuzy]

That's 4 alk readings compare to 90 days x 8 readings a day. S lot could change in 90 days.


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[Ranjib Dey]

Triton does not give alk values

 

[Flagg37]

Triton does not give alk values

Right, triton doesn’t but the icp testing that @rygh did performs an extra test for it and includes it with the results. The triton test also doesn’t cost $25/test like the other icp test does.

 

[rygh]

Yes, meant ICP.