ULR Phosphate checker vs control sample

[jcates]

I purchased the calibration set/control sample from Hanna to check against my ULR Phosphate checker.

The control sample was .4 and mine read .37 so within the acceptable margin of error.

Question is will the checker I have always be .03 low on every reading going forward? Just curious

I get it is not a significant difference. Well I guess that depends on who you ask.

 

[windemerejack]

There are lots of things that can cause any outcome to a test, just do 5 tests after each other using the control and see if it always reads 3.7.

 

[ReeferLou]

cleanliness of the cuvette and bubbles on the inside may be factors.

 

[jcates]

There are lots of things that can cause any outcome to a test, just do 5 tests after each other using the control and see if it always reads 3.7.

This would bring me to the next question that I forgot. Why do you suppose it says the control can only be used once?

 

[jcates]

cleanliness of the cuvette and bubbles on the inside may be factors.

Did that even wipes with their rag. The .03 is within the margin of error with the checker.

 

[windemerejack]

This would bring me to the next question that I forgot. Why do you suppose it says the control can only be used once?

where does it say that?
It has a use by date on the box it comes in so its use is for more than once

 

[jcates]

where does it say that?
It has a use by date on the box it comes in so its use is for more than once

Says it here in the fine print. Seems suspect to me but I'm no chemist.

 

[windemerejack]

Never noticed that before, it contradicts the line above which says acceptable results, which is plural, which means more than one, so you must be able to use it more than once. Dont quite understand that myself.
Maybe somebody @Hanna Instruments can clarify this?

 

[X-37B]

IMO, a 0.03 range is just fine for a hobby test kit. Set your desired range for the tank.
Example: my range is 0.02 to 0.1 and most of the time its 0.06.
So its close enough for me.
If its off by 0.03 its really not going to matter.
Its the variation of your tank sample is what matters as long as its within your range

 

[jcates]

IMO, a 0.03 range is just fine for a hobby test kit. Set your desired range for the tank.
Example: my range is 0.02 to 0.1 and most of the time its 0.06.
So its close enough for me.
If its off by 0.03 its really not going to matter.
Its the variation of your tank sample is what matters as long as its within your range

Agree 100% that margin is certainly acceptable. But there are those that would disagree. Funny how if we are within the range you stated we are fine but if it's .13 then it's panic mode and surely the cause of all death in the tank. ....lol

 

[jcates]

I guess I should also confess, I have been known to panic before I have to remind myself to slow down.

 

[X-37B]

Says it here in the fine print. Seems suspect to me but I'm no chemist.

I had to go check mine after looking closer at this.
Mine does not say that but its the ppb version. It does have an experation date though.
Either way trying to control any parameters in to tight of a range can be problematic.
Also panic is the kiss of death in this hobby, lol.
If your test is off by .03 and the tank looks good why panic!
Many get into the change/reduce everything mode when they have an issue. Again, KOD.

 

[jcates]

Well that's strange... You'd think it's would have the same basic ingredients in the reagent just different concentrations