Rise is Alkalinity. Issue with reagent?

[blalaw87]

Good Morning!

I was testing my water this morning and was measuring Alkalinity with the Hanna checker that I have.

from the last time that I checked it on Oct 18th it went from 7.2 dKH to 7.9 dKH. That seems like quite a big rise. I was wondering if it could be from the reagent that I am using? I have noticed when I am pulling out the reagent that I am mixing in with my tank water that there are some items floating it in and I try to stay away from them. The date on it says it is good well into next year so I was not sure.

Also I wanted to check if the rise in dKh is that big of a deal or it is something that I shouldn't be worried about? I know that I want to try and stay away from big swings but am not sure how concerned I should be about something like this.

Thanks!

 

[Randy Holmes-Farley Verified Community Expert]

That rise is close to the testing uncertainty of the device (+/- 0.6 dKH for a difference of two readings), even if there was no actual rise, and I'd just keep monitoring it:

Saltwater Aquarium Alkalinity Colorimeter (dKH) Checker® HC

The HI772 Marine Alkalinity Checker®HC (Handheld Colorimeter) provides a simple, accurate and cost-effective way to measure alkalinity as dKH (degrees of calcium hardness).

www.hannainst.com

Accuracy @ 25°C/77°F

±0.3 dKH ±5% of reading