Hanna Colorimeters

[Magickiwi]

Is there a way to calibrate a Hanna checker? I bought the low range phosphate one and it is showing my tank as .14ppm and three chemical tests show my phosphates as around 0.01ppm. I'm thinking if my phosphates were that high I'd have huge algae problems and my livestock would be on deaths door, and the truth is my system is thriving.

FYI avoid an internet retailer called eseasongear.com. Took 3 months to get my order and the silica colorimeter I bought was obviously used. It was physically broken and missing all of the "c" reagents.

[Werbo]

Chances are the hanna is accurate. Phosphate of 0.14 though not ideal is really not that bad and would not affect livestock.

[Reef Pilot]

Believe your Hanna. I used to test with other chemical kits and used to think my phosphate was zero. When I got the Hanna, it showed phosphates, and took a while longer with GFO before it read zero, too.

[Magickiwi]

Well according to the documentation the Hanna unit checks for a type of phosphate that the chemical kits don't detect. I took that to be marketing BS.

Well to be on the safe side I changed out my rowaphos and put a phosphate filter pad in my sump. Put in approx. 150ml of new rowaphos but it didn't drop the level over night.

I am dubious about the accuracy of the meter though. Need to find a reference test fluid for it.

[lastlight]

you're using the Hanna Phosphate or the ULR checker?

[Magickiwi]

Originally Posted by lastlight

you're using the Hanna Phosphate or the ULR checker?

Phosphate low range, not the ultra low range.

[Magickiwi]

Any more advice out there? I was thinking of taking the reference sample from my seachem kit, diluting it 50% with RODI water and running a reference test with that. The Seachem kit has 1mg/L reference sample but there's not enough for my 10ml test tube in the Hanna. So in theory if I dilute by 50% then I'd have a sample that's .5mg/L or very close to .5ppm.

Sound theory?

[sphelps]

mg/L = ppm for pure water only since 1L = 1kg. So your conversion will be off. Personally I would go by the Hanna and deem the other kits inaccurate.

[Magickiwi]

Originally Posted by sphelps

why not test RO/DI water? Should be zero right? So if the Hanna tests over it should be pretty obvious.

Hmm good idea. Worth a try.

[Cal_stir]

I don`t think po4 shows up on tds meters so even if you have 0 tds you could have po4
I had a hanna phosphate checker and it was a POS, I thru it in the garbage, I have ordered a hanna phosphorus ulr as i read they are much more accurate, they measure ppb phosphorus which is mathematically converted to po4