Probes/Ion Selective Electrodes

[YankeeTankee]

Which lab grade probes/electrodes are useful in reefing, more accurate than hobby kits, and relatively easy to use? I'm not sure if "ease of use" is probe manufacturer specific or more holds true for all probes testing X. Would any of these or others fall in the "accurate and easy to use probe" category meaning easy and or infrequent calibration and whatever other considerations there are. I'm thinking for periodic not continuous use as I've heard of biofouling if left in, of course if continuous use is possible do tell. Neglect budget but no 3k probes lol. Of course these parameters come to mind:
Ca
Alk
Phosphate
Nitrate
mag
potassium
conductivity
ph
whatever else I am forgetting.

I'd just like to call out two parameters specifically.

Conductivity, I know Randy has used a 4 electrode conductivity probe, he just drops it in and it works without even calibration. Are most conductivity probes like that? I was looking at https://www.thermofisher.com/order/catalog/product/013020MD#/013020MD Also the readings are temp compensated, in order to calculate conductivity you need temp so this just ensures I am getting an accurate reading at say 80F?

Last one I want to call out specifically - ALK, so the thermofisher site says "Measure carbon dioxide, carbonate and bicarbonate in aqueous solutions quickly and accurately with the Thermo Scientific™ Orion™ 9502BNWP Carbon Dioxide Electrode." Would this probe give results that could easily be used interpreted like the dkh readings we see all the time? Or are our hobby grade kits not testing for all of these 3 and theres an issue? Same question as for all about ease of use also.

Thanks so much, apologize for the length of the post!

 

[LadyTang2]

Interesting, hach lists different types of probes I wonder which would be best/require less calibration - they have conductivity probes that are dig or ana conducting, dig or ana indcuctive, electrodless, cation conductivity, DCCP system. Wonder how these compare to the 4 electrode from thermo you mentioned.

Also this comes with the meter and probe, some of the models have conductivity, I wonder how accurate this is compared to hobby on low end and thermo 4 probe on high end. Like this

Sension+ MM156 Portable Multi-Parameter Meter, Field Kit with Multi Sensor for pH, Conductivity, Salinity and Dissolved Oxygen (DO) | Hach USA - Overview - Obsolete

Sension+ MM156 Portable Multi-Parameter Meter, Field Kit with Multi Sensor for pH, Conductivity, Salinity and Dissolved Oxygen (DO)

www.hach.com

or

Sension+ MM150 Portable Multi-Parameter meter, Field Kit with Multi Sensor for pH, ORP, Conductivity and TDS | Hach USA - Overview - Obsolete

Sension+ MM150 Portable Multi-Parameter meter, Field Kit with Multi Sensor for pH, ORP, Conductivity and TDS

www.hach.com

I think some of these specific ion probes you mentioned get thrown off by saltwater, Randy will probably know.

 

[Randy Holmes-Farley]

IMO, there are very few, if any, that won't have interferences that will greatly complicate the interpretations, and which will require one to make standard curves with the actual tank water.

Conductivity, obviously, is a great method. Dissolved O2 is also good.

The electrode linked in the first post is a perfect example of what I mean. You do not drop it in and get a reading. You need to do complicated standarization of the tank water. The manual has many pages devoted to how to do that:

Thermo Scientific™ Orion™ 9502BNWP Carbon Dioxide

Document Connect

www.thermofisher.com

 

[YankeeTankee]

IMO, there are very few, if any, that won't have interferences that will greatly complicate the interpretations, and which will require one to make standard curves with the actual tank water.

Conductivity, obviously, is a great method. Dissolved O2 is also good.

The electrode linked in the first post is a perfect example of what I mean. You do not drop it in and get a reading. You need to do complicated standarization of the tank water. The manual has many pages devoted to how to do that:

Thermo Scientific™ Orion™ 9502BNWP Carbon Dioxide

Document Connect

www.thermofisher.com

Thanks, sounds like probes are good for conductivity, pH, DO, ORP, and not much else useful in aquaria.

The probes I see are for manual use not to be left submerged. Randy are you familiar with any fancy grade probes/meters that are appropriate for continuous use? A probe I can leave in the sump and it's meter will record data on ie conductivity with good accuracy (more than apex/ghl). I realize it could be quite costly, anything come to mind that's durable, won't contaminate water, not have biofouling issues, etcetera?

 

[Randy Holmes-Farley]

Thanks, sounds like probes are good for conductivity, pH, DO, ORP, and not much else useful in aquaria.

The probes I see are for manual use not to be left submerged. Randy are you familiar with any fancy grade probes/meters that are appropriate for continuous use? A probe I can leave in the sump and it's meter will record data on ie conductivity with good accuracy (more than apex/ghl). I realize it could be quite costly, anything come to mind that's durable, won't contaminate water, not have biofouling issues, etcetera?

I've periodically looked around to see if there are any other probes useful for us, and not found any, but have not done so recently.

Folks trying to develop continuous read devices have either gone to optical measurement with films that bind ions (like the Mindstream or Seneye) or automatic titrations (essentially a robot kit).

 

[jccaclimber]

What do these probes live in when not testing? Do they need to be in a special solution or is air / RO water sufficient?

 

[Randy Holmes-Farley]

What do these probes live in when not testing? Do they need to be in a special solution or is air / RO water sufficient?

Depends on the probe. The one I posted a link to says:

Storage Solution, Cat. No. 941706 – To store the electrode, 0.1 M sodium chloride (NaCl).

 

[chadfish]

I've periodically looked around to see if there are any other probes useful for us, and not found any, but have not done so recently.

Folks trying to develop continuous read devices have either gone to optical measurement with films that bind ions (like the Mindstream or Seneye) or automatic titrations (essentially a robot kit).

Randy, have you seen the Vernier ones? They have all the standard ones plus nitrate. Any thoughts about using these in an aquarium?

Nitrate Ion-Selective Electrode - Vernier

The Nitrate Ion-Selective Electrode (ISE) can be used to measure the concentration of Nitrate (NO3-) in aqueous samples.

www.vernier.com