kH keeper plus "no reagent"

lmfbs · Mar 9, 2024

I purchased a second hand kH keeper plus and it seems to be working except that all the tests come back at 15dkH and say "no reagent".

I've seen this seems to be an error code, so I'm trying to troubleshoot.

- I've calibrated at pH4 and pH7 and done an accuracy test which seems fine
- I've mixed a second batch of reagent (100ml reagent, 900ml RODI) and tested using the second batch with the same result. The reagent "expired" in Dec 2023 but it's HCL and that doesn't really make sense. For the second reagent mix, I used an unopened (but Dec 23) bottle.

What I'll try next:
- accuracy test of the other pumps (reagent and aquarium pump)
- I wonder if the pH probe needs to be replaced. I'm not sure how old it is or how it was taken care of, so I might just bite the bullet and pick up a new one

Anything else I'm missing?

lmfbs · Mar 11, 2024

An update to this:

I've accuracy tested the other pumps and they're all within range just fine
I have bought some more accurate measuring cylinders to measure the reagent. I'm hoping they arrive over the next couple of days.
I haven't yet ordered a new pH probe because it appears to be working fine at the moment. It probably does need to be replaced, but I don't think that should cause the issue I'm seeing (it looks like a pH probe that needs to be replaced tends to need calibration more frequently).

So this means I'm stuck with perhaps the reagent has gone bad? Might post in the chemistry forum!