Hanna PO4 Checker - Low vs Ultra Low

[Fisherman Joe]

Well this isn’t good.

My low range checker is a few years old but this is the same water sample.

 

[Doctorgori]

BRS did a great vid on this, but short ans. I’d trust the ULR ...
I tossed the other one but it lasted a while

 

[Fisherman Joe]

Agreed.

 

[Big E]

Is the checker on the left the 714? If so that's very common. Once you get levels below .10 accuracy is an issue.

The 736 and 774 are the models to use. You also can't use 774 reagent in the 736 as the readings will show lower in the 736 as in your picture.

 

[Fisherman Joe]

Yes it seems you are correct. I wonder how many corals I have lost with the PO4 swings due to the 714 reading zero?! My reaction is always to over feed after.

 

[Big E]

Yes once you hit zero or very low on the 714 you really don't know where you're at. I would normally get a difference of about .04-.05 which is the accuracy swing of the 714.

The 736 reads up to .60 so no need for the 714 as if you're that high or above you'll need to do some correcting down.

 

[Fisherman Joe]

I have the 774 now.

that’s showing 0.10 often.