Mini heart attack! Problem with hanna alk fluid?

[Jake_the_reefer]

So I did my weekly alkalinity test on my 20 gallon tank. Last reading it was 7.5dkh but today when I measured it was 15dkh!!!!! Immediately I started to prepare fresh salt water and double checked my reading on the hannah checker.... this time it read 7.7dkh.
When I looked at the Cuvette that read 15dkh there was a ton of thick slimey percipitate. Does hannah alk fluid expire within 3 months of opening?

 

[W1ngz]

Does hannah alk fluid expire within 3 months of opening?

There's an expiry date on the reagent box, or the kit box if its your first bottle.

Thick slime sounds more like leftovers from a previous test. How confident are you that the cuvette, lid and syringe was cleaned and rinsed last time when you finished, and was it all rinsed again before starting?

 

[Jake_the_reefer]

There's an expiry date on the reagent box, or the kit box if its your first bottle.

Thick slime sounds more like leftovers from a previous test. How confident are you that the cuvette, lid and syringe was cleaned and rinsed last time when you finished, and was it all rinsed again before starting?

I fill with rodi and vigorously shake. Then fill with tank water and shake then I finally fill it and do my test. I didnt clean the pipette so its entirely possible it was in the pipette

 

[Jake_the_reefer]

Just checked. My reagent is good til next year

 

[W1ngz]

I didnt clean the pipette so its entirely possible it was in the pipette

I usually take a small cup of RODI to rinse the cuvette, as well as suck some into the pipette tip when I'm finished. I store the cuvettes full of RODI to be sure nothing cakes or crusts on the inside, and store the syringe and rubber tip separated from one another to make sure they dry.

 

[X-37B]

I keep DI in the cuvettes until I use them. Once a month I fill with vinegar and flush.
Always recheck or use another test to verify before making adjustments to the tank.
The older the solution the more of the chunks as some call them are present in the bottle from my experience. It does not change the readings though.
Hanna has still not said what it is but to just let it settle before pushing the button.

 

[Jake_the_reefer]

I usually take a small cup of RODI to rinse the cuvette, as well as suck some into the pipette tip when I'm finished. I store the cuvettes full of RODI to be sure nothing cakes or crusts on the inside, and store the syringe and rubber tip separated from one another to make sure they dry.

I'll do that from now on!