NO3 test solution.

[rkilling1]

Why do we not mix up some KNO3 to a proper level and dilute it down and use it as a test solution for our NO3 kits? I keep hearing that a NO3 level of 5 or even 10 could mean 0.

We all Know that our test kits are junk, but why not figure out how much KNO3 it would take to make a 10 PPM solution and see where we stand. Heck way not make a whole calibration curve set.

I am sure there is a chemist/math major who would love to figure this out.

granted it would take an accurate scale and a volumetic to perform.

but what accuracy are we looking at +- 10%

even with an accuracy of +-25% at 5 PPM is still way better then 0. using a tsp and a cup I bet I could get that accuracy.

unless KNO3 is hygroscopic, then nevermind. anyone have a desiccator.

 

[malkore]

all you need is Chuck's calculator, and you can mix up a 1gallon bucket to Xppm of NO3, and then test it.

for example, .1grams of KNO3 will yield 16ppm of NO3 in 1gallon of water.

but even doing this to validate your test kit still won't give it the ability to discern low ppm's of NO3 from 0ppm of NO3.

I will say, however, that my Aquarium Pharm. test does just fine at determining 0ppm, 5ppm and 10ppm. I've validated it against a LaMotte twice, and a SeaChem kit (generally considered the 'best' hobby grade kit until you jump up to Hach or LaMotte)

 

[Purrbox]

One thing to note. Make sure to use RO water or another source that you are certain doesn't contain Nitrates, otherwise your calibration solution could be inaccurate.

 

[dapellegrini]

Either my Seachem kit doesn't work, or I am completely inept. It registers 0 or some strange orange color, instead of a shade of purple/pink... Even stranger, the calibration solution that it comes with works correctly, showing 10ppm... ??? So I picked up a Hagen kit and find it hard to read (differences in the colors are very minor and represent huge jumps, i.e. 50ppm and 100ppm look almost identical). I can now find me out in the sun against a white piece of paper asking other peoples advice on which shade it is (and no one seems to agree).

I have heard a lot of talk about LaMotte... Is that an expensive kit? Where do you find them? I haven't seen it on my usual retail sites...

 

[rkilling1]

all you need is Chuck's calculator, and you can mix up a 1gallon bucket to Xppm of NO3, and then test it.

for example, .1grams of KNO3 will yield 16ppm of NO3 in 1gallon of water.

Nice and easy, but .1 grams will still be difficult for the average joe.

but even doing this to validate your test kit still won't give it the ability to discern low ppm's of NO3 from 0ppm of NO3.

My point was, if you can make a solution that was 5 PPM NO3 or close to, you can tell if you can discern 5 PPM NO3 or not.

One thing to note. Make sure to use RO water or another source that you are certain doesn't contain Nitrates, otherwise your calibration solution could be inaccurate.

good point

 

[Purrbox]

Lamotte kits are expensive. Best price I've found was at Marine Depot.

As far as measuring out .1g of KNO3, it's really easy. Just pick up a digital gram scale that's accurate to 0.1g on ebay. Should run about $20-25 shipped. This works great for measuring out your dry ferts for dosing and/or mixing solutions. This will be a LOT less expensive than shelling out the cash for a LaMotte Test kit.

 

[rkilling1]

As far as measuring out .1g of KNO3, it's really easy. Just pick up a digital gram scale that's accurate to 0.1g on ebay. Should run about $20-25 shipped. This works great for measuring out your dry ferts for dosing and/or mixing solutions.

I should probably get one of those. better then just guessing with the walmart tsp.

Lamotte kits are expensive. Best price I've found was at Marine Depot.

That's not too bad. HERE is one of my other test kits. now those get a little expensive.

 

[Zezmo]

Is it possible to either increase or decrease the number of drops used from the test kit, to increase sensitivity to low ranges?

 

[malkore]

Is it possible to either increase or decrease the number of drops used from the test kit, to increase sensitivity to low ranges?

nope.

 

[Plantbrain]

Hanna makes a colorimeter NO3 test kit, runs about 175$.
Lamotte's is not bad, about 50-60$ for 0-15ppm

These two are very good in terms of auccuracy, the same cannot be said for the hobbyists brands.

You must calibrate them if you plan on confidence in them.
Some can be used in relative units, e.i, your tank does well when it's a orange color on the test color chart etc.



Regards,
Tom Barr