Massive Alkalinity Spike- or bad tests?

W00F · Mar 31, 2020

Hey Everyone,

I’m a bit confused and frustrated right now.

For months my Alkalinity tracked my dosing and water changes. In my 20 gallon, it’s lately been needing about 2.25 ml of Alk per day to keep it at 8.5. Calcium remains steady without dosing around 420.

I just replaced my Hannah All reagent and my reading went from 8.4 dKh last night to 10.0 tonight!!! I tested again and it was 10.1.

I tested some saltwater that should be a little more than 7.0 and it was 7.4. The pH is is 8.3 or a bit higher.

My old reagent wasn’t expired and it never seemed odd with test results. Always dropped about 0.2 dKH a day and I dosed 2.5 ml - 5 ml to keep it at 8.5.

Does anyone have any idea what is going on? Did I get a bad reagent originally do you think?

homer1475 · Mar 31, 2020

Lets start with this....

Do you only do 25 tests, or did you use up the reagent?

Reason I ask is I have found through the years of using the Hanna ALK kit that if you try to use the last bit in the bottle instead of the stated 25 tests, it will read significantly lower then what it actually is compered to a new bottle of reagent.

Since I stopped using the last bit, and marking each bottle so I only use 25 tests, my numbers have been much more consistent bottle to bottle.