Will we ever see an Alkalinity Probe?

[tonyespinoza]

I assume there's a (non-market-driven) reason why Pinpoint hasn't made an Alkalinity Meter. Would love to learn from the experts the explanation of why this is from a chemistry/implementation perspective....

Seems like it would have a huge impact on the hobby -- for me it's probably been the biggest key to success.

 

[Randy Holmes-Farley]

Alkalinity is not a single thing in the water, so such a simple probe is not possible. I have discussed the issues with a hobby company that is thinking on/working on a probe that can give similar information, but it is not yet ready for prime time.

 

[tonyespinoza]

well, if you can crack the code do let us know! the best test i've found is the LaMotte kit but of course you've got to test multiple times a day to get a complete picture of what's going on. so something resembling a meter that measures (or proxies) some indication of alk would be super cool. I guess pH is a useful guideline, but do the daily swings in pH directly and consistently correlate to swings in Alk?

 

[Randy Holmes-Farley]

No, pH swings will be lower at higher alkalinity, but have perhaps more to do with aeration and photosynthesis levels.

 

[Julian H]

They make them for science labs, but if you use them without giving them a break pretty often they die. I assume thats the reason.

 

[OCEAN SIZE]

Great question. You're on a roll tonight Tony.

I'd like to buy one when they come out...

 

[Randy Holmes-Farley]

They make them for science labs, but if you use them without giving them a break pretty often they die. I assume thats the reason.

An alkalinity "probe"? I don't think so. Maybe a complex machine that does an automatic pH titration for you (we have those), but that is not a probe.

The closest you might come is a bicarbonate probe, and I've not seen those commercially available that would work in seawater. If that could be made to work, it would be an alternative measure that would be just as useful, but would not yield alkalinity.

 

[dots]

Could a Ph probe be used to see the rate at which Ph is allowed to change with respect to time and used this to determine the alkalinity?

Just trying to think about what Alk at its different points effects that we CAN measure.

If not, can you think of another possible metric?

 

[Randy Holmes-Farley]

All an alkalinity test kit is is a measure of how much acid it takes to drop the pH into the 4's. One can do that with a kit or simple addition of a standard acid and a ph meter, but not a change with time unless you are adding an acid at a standard rate. I discuss what alkalinity is and how to measure it with a pH meter and a standard acid here:

What is Alkalinity
http://www.advancedaquarist.com/2002/2/chemistry

If not, can you think of another possible metric?

As I mentioned above, there is a way to do it with another type of device, plus a pH measurement, but since I'm discussing that with a manufacturer, I'd rather not also discuss it publicly until it is ready. It is not a DIY method.

 

[tonyespinoza]

go randy go! i think your device could revolutionize the industry. if folks could manage Alk like they do other simple parameters like temperature... a lot more folks would be successful.

please PM me if you want any help. i'm an entrepreneur in silicon valley and know a lot of investor-types. i've had a few successful companies and would be happy to open any doors or help in any way i could.

 

[MCsaxmaster]

I've heard through the grapevine that Dr. Frank Millero at RSMAS has been working on something along these lines (he's one of a couple of people that wrote the book on seawater alkalinity, pH, etc....and I mean that literally ). I don't know any details yet, but I'd be very interested to see what he's doing. Whatever it is, I'm sure it would not be for hobbyist application--at least not yet.

Chris

 

[dots]

This is what I was thinking of and using with a little Calc, a timer, and a known acid as you mentioned.

 

[Herzberg]

www.eneye.se states to have an alk probe... How can that be if it's not possible?

 

[Randy Holmes-Farley]

Sorry, I cannot read that language. What do they claim? I guarantee there is no such thing as a simple alkalinity probe. A bicarbonate ion selective electrode, if such a thing were developed for seawater, could give an alternate measure that would be just as useful for reefers, but it alone will not give alkalinity.

This is what I was thinking of and using with a little more, a timer, and a known acid as you mentioned.

That could be useful, but would not be a "probe", and would likely be no easier and would be more prone to errors than simply measuring the acid it takes to drop the pH to 4, which is the definition that I showed in the linked article above.

 

[talon4x4]

<a href=showthread.php?s=&postid=12744153#post12744153 target=_blank>Originally posted</a> by Herzberg
www.eneye.se states to have an alk probe... How can that be if it's not possible?

The page is in Swedish, but I can't find a decent translation of it.

 

[Qcks]

Well... like Randy has stated a bicarbonate probe would probably not be possible but....

Just off the top of my head, why not make a pressure chamber that injects concentrated carbon dioxide under a known temperature and pressure and then measuring the difference between the Carbon Dioxide injected and carbon dioxide given off after being exposed to the water?
Wouldn't The difference between the amount of Carbon Dioxide injected versus Carbon Dioxide recovered be inversely proportional to the concentration of Bicarbonate and Carbonate Ions in the water?

 

[Randy Holmes-Farley]

That would be easier than a pH titration?

 

[Qcks]

well.. i suppose not. just thought it might be something that could be done as a continuous monitoring sorta deal. constantly comparing the amount being inject compared to the amount given off.

You're right easier isn't perhaps the word to describe it. I just thought it'd work better then doing multiple titrations throughout the day.

 

[Randy Holmes-Farley]

I don't want to get into details, but a dissolved carbon dioxide measurement is part of what I had in mind that I've suggested to the company mentioned above.

 

[kmckay]

JMO, but is seems like continous monitors are only useful for measurements that change quickly and can be corrected quickly. Such as by responding to a dangerous temp spike by turning out the lights or hooking up a chiller. Test kits seem to me perfectly sufficient within the context of alk management which involves slow, deliberate alterations of a dosing regimen.

Though if implemented as a controller for a calcium reactor, I can see that it might offer advangages over a pH contoller...

Just some thoughts.