Ion Selective Electrodes (ISE)

[nomsmon]

Does anyone have experience with diy solutions utilizing Ion Selective Electrodes?

I haven't heard much about their use in the aquarium industry, but I did find a press release for GHLs ION Director which mentions they developed a multi-Ion Selective Electrode.

Also wondering if ISE in a marine aquarium require a reference EC measurement due to the high conductivity of seawater?

 

[theatrus]

Haven't toyed with them, but they do exist for some interesting types, like Ca+, and a Ca/Mg less-selective type.

https://pim-resources.coleparmer.com/data-sheet/m40501.pdf
https://www.aquariumcomputer.com/products/ion-director/
Looks like its basically a pairing of common electrodes. Those Cole-Parmer models are pricey as expected for an analytical electrode ($300 for Ca+), but probably can be had cheaper from direct imports? I'll need to check around a bit.

IMHO the Ca and Ca/Mg are the most interesting, as it can be a proxy for calcium uptake.

 

[nomsmon]

I was also looking at those Cole-Parmer ones; some very interesting options for sure.

ISE definitely seem to be pricey, but the idea of not having to stock reagents for something like a colorimeter based tester sounds nice.

 

[nomsmon]

The replacement probes for the Pinpoint sensors might be a decent retail option. At ~150USD they are certainly cheaper than the Cole-Parmer or Hanna ISE

 

[theatrus]

The replacement probes for the Pinpoint sensors might be a decent retail option. At ~150USD they are certainly cheaper than the Cole-Parmer or Hanna ISE

Good find, curious to do some testing :)

 

[nomsmon]

Good find, curious to do some testing :)

If you feel up for the adventure I also found a bunch on ali-express, but can't find a datasheet for any... Which puts them outside my comfort zone lol

 

[theatrus]

If you feel up for the adventure I also found a bunch on ali-express, but can't find a datasheet for any... Which puts them outside my comfort zone lol

Most seem to resells of the REX electrodes:

https://shrex.en.alibaba.com/productgrouplist-804075124/REX_electrode.html

 

[nomsmon]

Nice find. I tried searching for Rex and couldn't find anything.

I'm guessing these function similar to a pH probe? So connect them to a similar type of voltage measuring circuit?

 

[robsworld78]

Does anyone have experience with diy solutions utilizing Ion Selective Electrodes?

I haven't heard much about their use in the aquarium industry, but I did find a press release for GHLs ION Director which mentions they developed a multi-Ion Selective Electrode.

Also wondering if ISE in a marine aquarium require a reference EC measurement due to the high conductivity of seawater?

No experience but they have a quite a few and what's nice when you view a probe and go to requirements they have plenty of resources to get them working, should be the same for other brands.

https://www.vernier.com/product-category/?category=ion-selective-electrodes

 

[theatrus]

Nice find. I tried searching for Rex and couldn't find anything.

I'm guessing these function similar to a pH probe? So connect them to a similar type of voltage measuring circuit?

Yeah, looks to be effectively the same. They may require different gain depending on the sensor element range, but thats easy to adjust. Most calibration solutions are two point (10, 1000ppm, or sometimes higher) which is perfectly in range.

 

[theatrus]

No experience but they have a quite a few and what's nice when you view a probe and go to requirements they have plenty of resources to get them working, should be the same for other brands.

https://www.vernier.com/product-category/?category=ion-selective-electrodes

Good find, never ran into their little interfaces before.

 

[chadfish]

Vernier has a great selection with replaceable membrane modules. Has anyone used these? They interface with an arduino amongst other things.

https://www.vernier.com/product/nitrate-ion-selective-electrode/

 

[ReefStable]

Out of curiosity, has anyone interfaced these ISE probes with a controller (Apex, Hydros, GHL, etc) or even with an arduino/raspberry pi?