False Hanna Colorimeter Readings

[Fatboy]

This last week I was getting really worried since I started noticing that my phosphates were climbing out of control no matter what I did in my tank to avoid that to happen. Basically, my Hanna Colorimeter was indicating that my levels were at 0.12

Last night I check the levels again, and the colorimeter registered 0.11. I was intrigued and decided to check if there was any visible color in the water being tested and I found that the inside of the glass container was full of tiny micro bubbles.

When I put the reagent into the glass container, I place the plastic top and the I shake it for a couple of seconds in order to dissolve the reagent. Then I put it in the colorimeter and press the 3 minute reading button. The problem is that this shaking is creating a lot of micro bubbles.....

When I took out the glass container and I noticed that I had this bubbles, I tried to shake it a little bit more to get rid of them and after that, the next reading went down to 0.04. So now I'm wondering how accurate are these measurements. It is clear to me that the presence of microbubbles can interfere with the reading and as a result, you would get false readings.

Anybody with a similar problem ? How you guys have solved this issue ?

 

[prodman]

Dont shake it. Very slowly turn in over so you dont create the micro bubbles. And the 3min is just a timer so I take it out with 30 sec or so left and check for bubbles and slowly turn it to relese them if present.

 

[manderx]

you can knock a bunch of the bubbles free by tapping the vial on a table or something. i also had a huge problem with bubbles in mine, even when i gently swirled so now i mix in a separate vial (old salifert test tube) then transfer it to the cuvet for testing.

 

[prodman]

The separate mixing container is a good idea

 

[jamesdawson]

I hate how small Hanna made their tubes. Besides bubbles, they are really hard to dry out after rinsing (I finally started using Q-Tips).

My old Medusa Colorimeter was a much better unit and tested multiple parameters, unfortunately the reagents were changed by Hach so you can't get reagents for the Medusa anymore. The vials on the medusa were wider and I never had bubble problems or cleaning/drying problems.

James