Maybe someone can help me understand my Hanna P04 LR?

[Reefin' Alaska]

I got tired of using my Red Sea kit, they are expensive to replace and taking around 16-17 mins a test to get a result isn't ideal.

I bought a Hannna P04 LR H713 tester, with an extra set of reagents. It constantly reads 0. I have no idea why.

I purchased a Phosphorus ULR tested from my LFS yesterday, it read 20 twice in a row. About .06 which I do believe is accurate. My Red Sea kit, I don't have the green wheel anymore as I was getting rid of it, but I just dug it out and tested with it and it definitely turns green.. It's not 0.00 the Hanna LR gives me.

It's brand new, and I don't completely understand why it continually reads 0. I've tried multiple cuvette's, microfiber, the 10ml letters orientated the same direction every time. I'm a little baffled at this thing.

 

[CasperOe]

Check out this thread on the same subject, should tell you everything you need to know about the difference between the two

IMO, only the 774 is useful in our hobby.

 

[MrGisonni]

The low reader is not very accurate and really designed for fresh water. I was reading zero with a low reader and then read the thread that's probably linked above. The ultra low reader that actually has the saltwater symbol on it is the one you need. I purchased the URL, Now my tests have been consistent, and my phosphates are where I want them about .05-.06

 

[Reefin' Alaska]

Went out and bought a 774 this afternoon. Low and behold, .06..

Which is exactly where the Phosphorus was. But, like you said it needs a conversion.