Does DI Water 'Absorb' NO3?

[Fishfreak]

I started using DI water for water changes and top ups about a month ago.

Fresh from the DI unit, NO3 measures 0 (this is an industrial size deioniser the height of a man- not a hobbyist version). I see little improvement in my N03 level and decided to test the DI water that's been sitting in the top up water pail for a week.

NO3 measured around 40ppm!

The DI water taht remains stored in sealed containers continue to measure 0 for NO3.

Question: Did the DI water 'absorb' NO3 from the air (?) when exposed to the environment?

Thanks

FishFreak

[Tanzy]

Maybe there's something wrong with the testkit.

Also, DI water must be stored in special containers specifically meant for it and totally sealed air tight. Plastic can leach stuff into DI water. Even just touching the water can contaminate it.

[Fishfreak]

The Salifert kit checked out OK. I tested the 7-days old DI water in the top up pail twice with the same result. 7-day old DI water sitting in sealed containers continue to test 0 for NO3.

I've now filled a couple of PET bottles, sealed them and will test for NO3 in a couple of days time.

FF

[arcanehacker]

wouldn't it be funny.. Where did the NO3 come from? .. DI or not DI, how can the water have any increase in NO3 without anything in it..