Hi764 Hanna Nitrite ULR

AcanthurusRex · Jun 1, 2020

Yes, I use this for NO3 using Red Sea reagents.
There is a long thread on this subject. Search for it.
The procedure calls for some simple curve fitting math.
Even if not perfect it gives you a number for the in between value rather than a complete guess. When compared to the colors the value has seemed reasonable.

Randy Holmes-Farley · Jun 1, 2020

Michelin said:
could you explain why so long to converge to a costant value?

if instead i insert 1 ml Salt Water plus 9 ml RO do you think i will obtain 3 minutes of convergences?

it seems I inserted 10 times water and result seems 10 times to have convergences in time rather than salifert instructions....

I'm not certain, but I suspect two reasons:

1. It may relate to the fact that nitrate kits do not try to detect all of the nitrate. They detect only a tiny fraction, like 1% of it, by converting that 1% into nitrite and detecting the nitrite. If you wait longer than the specified time, you may be converting a larger fraction of it. That's OK if you are independently making a standard. it is not OK if you use the nitrate kit color card.

2. Dilution beyond what they specify in the kit will slow the reaction, just as dilution slows most chemical reactions involving two or more species. In a typical reaction involving two chemical reactants, dilution by a factor of 2 may drop the rate by a factor of 4.

Michelin · Jun 1, 2020

In fact I use their instruction to detect the color and my finding to detect the result.... The easy stuffs is that the number you are reading is just to divide by ten and you get the correct No3

What is no good is to wait 40 minutes... Instead 3 minutes of standard instructions...

Michelin · Jun 1, 2020

AcanthurusRex said:
Yes, I use this for NO3 using Red Sea reagents.
There is a long thread on this subject. Search for it.
The procedure calls for some simple curve fitting math.
Even if not perfect it gives you a number for the in between value rather than a complete guess. When compared to the colors the value has seemed reasonable.

I saw your experiment and you hispire me to do something similar using salifert test kit that is very common here in Italy..

Randy Holmes-Farley · Jun 1, 2020

DId you try to see what happens if you take a reading at 3 minutes or 10 minutes? I know it isn't stabilized, but perhaps it doesn't need to be, since you are making a standard curve.

Michelin · Jun 1, 2020

What understood that salifert wait 3 minutes using 1ml salt water ho to convergence. If I wait 40 minute with 10ml salt water go to same color level... It means if I stop before color level will be lower and also precision will be lower... For sure I can do a correlation but I will loose precision for sure...

Also I think is I do the test as salifert suggest and add after 9ml of ro water the test time will be 3 minutes but dilution with ro water also decrease color intensity... So precision....