intermediate_noob;20094 said:
Thank you for the clarification. Once again, I was looking for the materials I would need to extend the body of the probe to make an area for the reference solution and the membrane. I will make sure to review the links in greater detail prior to responding again.
Sorry, I did not see the question as asked:
Rubber tubing that fits slightly over the tip, the caps often used on pH probes they are shipped with can work, I wanted something a bit meatier, so I wedged a piece of rubber vinyl tubing over it. Note; this was for a flat tipped pH probe.
Not the standard round bulb.
You do not want to extend the body, you want very close distance between the probe tip and the membrane, thus the idea to use a micro probe.
This will help improve response time by having less distance and less surface to volume ratio, as things get smaller, their S/V ratio goes down, thus they diffuse more rapidly/easily.
This is one reason why algae are not limited and very sensitive to nutrient levels vs plants. They have a really good surface to volume ratio for uptake.
Same deal here.
Just take a look at the ppt link in particular and think about adding a little KH ref solution on a flat tip, much like the drop checker ideas. Flat tip pH probe would be ideal, vs a round more common pH probe(this will improve response time).
Since you have a standard round tip, you do not need any thing to extend over those, just wrap the membrane around it and use a small rubber o ring, you can buy the membranes on line, and you can get an o ring at Home Depot or OSH.
The standard pH probe tips have a round tip with 4 plastic protectors around them, so as long as the membrane does not get ripped, you can use those.
Sand the edges of the plastic some, to smooth the edges.
You can also snip the plastic edges off, and add a rigid mesh basket and wrap that with the mebrane KH solution. Not sure where you might find it, but as plumbing shop might have a small strainer that might work etc. Use plastic, not metal.
Regards.
Tom Barr