Extend The 'life' Of Your Nitrite Test Kit By A Factor Of 5?

[Underwurlde]

Hello!

Now, i'm no chemist by a long chalk, but division IS one thing I can do.

I use a Nutrafin Test kit to assess the levels of NO2 (Nitrite) in my tank.

The instructions say to take 5ml of tank water and then add 5 drops from magical potion #1 and then add 5 drops from magical potion #2 and shake it all up and wait for the colour change....

Now, I may not be a rocket scientist (OK an engineer, granted), buuuuuuuuuuut surely:
ONE mil of tank water plus ONE drop of reagent #1 and ONE drop of reagent #2 will SURELY suffice to complete a similar test and thus extend the life of my Nitrite test kit by a factor of 5!

Of course I have tried this and it works fine for me (but no doubt someone out there is shouting NO YOU EEEEEEJITTTT)!

Any reasons as to why this is stupid (and copy & paste this for ALL other similar 'magic potion' test kits???

Andy

Oh, and anybody else notice that the 'add equal quantities instructions' do NOT mean that you get equal quantities of reagent #1 and reagent #2 in the kit!!!! Naughty Nutrafin!

 

[countdown]

Off the top of my head, i think with such small quantities there is a much much greater chance of error.

But i will need to try and see how it goes.

 

[Underwurlde]

Ahhh, yes of course.

However I use a measured syringe (not that pipette(sp?) thing that comes in the kit) to get my tank water so I guess thats as accurate as anything.

Andy

 

[countdown]

Yeah a syringe would be a lot better, i only have a 1ml pipette (depends how hard you squeeze it, too how much you get )

 

[vic]

And,,,,,,,,,,,,,,,,,,,,,,,,,,,, will that extend the kit beyond it's best before date!
just a question.
Cheers;

 

[Underwurlde]

And,,,,,,,,,,,,,,,,,,,,,,,,,,,, will that extend the kit beyond it's best before date!

*Nah, not unless a live culture is used as part of a test?

But what do I know? I'll tell you: Absolutely nowt. So perhaps a chemist out there can confirm...

For my Ammonia (NH3 / NH4) test kit, the chemicals used are:
(Solution of) Sodium Hydroxide & Mercury Diiodide

For my Nitrite (NO2) test kit, the chemicals used are:
Reagent #1: Hydrochloric Acid (That's stomach acid isn't it?)
Reagent #2: Acetic Acid
(The combo gives Sulfanilic Acid I think???)

Andy

(*) Also there is no actual mention of an expiry date or sell by date on any of these packets & I don;t think any of these chemicals go off / evaporate / dissolve the container they are in....

 

[cs091]

For my Ammonia (NH3 / NH4) test kit, the chemicals used are:
(Solution of) Sodium Hydroxide & Mercury Diiodide

For my Nitrite (NO2) test kit, the chemicals used are:
Reagent #1: Hydrochloric Acid (That's stomach acid isn't it?)
Reagent #2: Acetic Acid
(The combo gives Sulfanilic Acid I think???)

Andy

(*) Also there is no actual mention of an expiry date or sell by date on any of these packets & I don;t think any of these chemicals go off / evaporate / dissolve the container they are in....

That isn't all thats in the test kits. The warnings only show you the dangerous ones. The kits need some coloured chemical to actually show the concentration of the thing you're testing for. And apart from mercury nothing there has coloured compounds.

If that reaction happens naturally as the reagent ages then you will get false positives - ie it will show nitrite or whatever, when there is none.

Conversely, if there is another reaction going on, for example with atmospheric oxygen - which you let into the bottle every time you open it - that changes the reagents, then the reaction to get the coloured result will not happen. And you get false negatives.

Without knowing the exact chemicals involved it's impossible to say what will happen. And of course if you knew the exact chemicals you could make the indicator kits yourself at half the price!

In principle it will work scaling down the reaction so if it encourages you to test more often the go for it!

 

[Underwurlde]

Hey thanks cs091 you seem well clued up in chemical 'things'.

IF these test packs do indeed deterioate (of course they will over a certain period of time, but if that period of time is say >5+years, then who cares?), then why is there no 'use by' date on the side of these packs? (I think I may have answered my own question there.

Anyway, I am beginning to think that extending the life of my kits (or more importantly shaving 80% off the cost of investment in chemical testing kits) is a not such a bad idea B)

Andy

 

[cs091]

Hey thanks cs091 you seem well clued up in chemical 'things'.

Andy

Having a degree in chemistry does help - even if it was tooo many years ago!

Water testing takes me right back.

 

[andywg]

Most of the test kits, especially nitrate, are only much cop for 6 months after opening. I have found a number of nitrate kits are wildly inaccurate from the off so refuse to trust them as an absolute result.

Most people stop testing with any great frequency once they are happy with the setup anyway. I can't remember the last time I tested my FW tanks.

 

[raptorrex]

sounds good BUT its a rule that works for all things, the smaller the sample you use the less reprisentitive it is!
having said that ill give it a try, if you do a 5mm sample and then a 1mm sample if the readings over time are the same its a winner

 

[Lord Zogat]

I have started doing the same with my ammonia test kit. Marked off 1/2 and 1/4 water amounts on the tube and only use 2 drops instead of 8 for the test and the 1/4 amount of water.

Since I am doing the fishless, so long as its not staying yellow, I have ammonia and the bacteria are not there yet. Also the reading was close to what I had when I first put in the ammonia which is about right, since I should see no major changes for 7 days.