Am i measuring incorrectly?

[Jake_the_reefer]

I have been monitoring my alkalinity with a hanna checker (new so not expired solution) and I have noticed a very odd thing. I had an alkalinity of 7.4 so I dosed some 2 part to bring it up. And I am seeing some weird results. The next day my alk was at 8.3.. okay sounds good it went up.. next day its 9.3 weird but okay... today 9.8. Am I using this thing incorrectly? I'm measuring at the same time of day as well and I'm not sure why my alkalinity would be rising unless I'm using the kit incorrectly. I measure out exactly 1 ml of reagent and ensure I fill the tube directly to the line with tank water. Is this normal?

 

[TheHarold]

Hmm, weird. I find my Hanna checkers to be very consistent. Are you remembering to put the lid on the reagent when you are done?

I always fill the vial with tank water, than empty it and fill it again to the line. To make sure its a good sample.

Make sure you are looking at the bottom of the meniscus.

 

[Jake_the_reefer]

Definitly doing something wrong just double tested and got 8.9

 

[Jake_the_reefer]

Hmm, weird. I find my Hanna checkers to be very consistent. Are you remembering to put the lid on the reagent when you are done?

I always fill the vial with tank water, than empty it and fill it again to the line. To make sure its a good sample.

Make sure you are looking at the bottom of the meniscus.

I dont rinse with tank water. I used tap.. that could have an influence. And yeah I've never left the cap off!

 

[TheHarold]

I dont rinse with tank water. I used tap.. that could have an influence. And yeah I've never left the cap off!

Yeah after you rinse it in tap, rinse it with your tank water and fill it. That tap water could definitely have an effect.

 

[Jake_the_reefer]

Yeah after you rinse it in tap, rinse it with your tank water and fill it. That tap water could definitely have an effect.

I'm doing that now. I'll rinse in tank water then run 2 tests and look for consistency

 

[Jake_the_reefer]

Okay. That was my issue. Both tests read 8.9 this time. The vials were not cleaned properly.. thank you for the help!

 

[W1ngz]

It's best to rinse test stuff with RODI when you're done.

With my hanna phosphate, I rinse the vial half full with RODI, dump it, then store it full of RODI so I know no deposits can dry inside of it. When I use it again, I pre-rinse it with tank water, dump that, then fill it for testing.

 

[Jake_the_reefer]

It's best to rinse test stuff with RODI when you're done.

With my hanna phosphate, I rinse the vial half full with RODI, dump it, then store it full of RODI so I know no deposits can dry inside of it. When I use it again, I pre-rinse it with tank water, dump that, then fill it for testing.

That seems like a good practice. I usually keep gasoline in mine I think I'll stop that. Haha just messing but I do like the idea to store rodi in it

 

[Justfebreezeit]

Rinsing well in RODI is definitely key for consistency. Espcially with the ULR phosphorus checker I noticed it starts giving my false high readings when my vile starts getting old (building up a film id imagine)

 

[W1ngz]

I usually keep gasoline in mine

Gasoline is fine, I don't think there's any sodium bicarb to throw off an alk test.
Totally reef safe as long as you don't smoke when you test ;Wacky

Seriously though, for those who read too close to the screen, don't do that