test kit?

[sam51]

hi all tested my tap water with a api nitrate test kit. followed the instructions,got a reading of
100ppm,probably higher,re tested the water with a tetra nitrate test kit. got a reading of 12.5 ppm.
i knew that a 100ppm was to high.so had a chat with veolia water,guy told me there latest readings
for my tap water is 43ppm. so phoned api,told them the situation,they sent out a new nitrate test kit.
still getting 100ppm.
so with api 2 test kits reading too high, and tetra reading too low, are these test kits a waste of time,
because i'm a bit confused,

[Koi Man Dave]

The uk legal limit is 50/Mgl this is also the standard for the EU also, bare in mind you could test once a week and you will no doubt get various readings providing its within the legal limit for human consumption there's not a lot you can do.
I know if you were to talk to your water company they will tell you the test kits we utilise are as a guide as they do not class them as accurate.

Having said this I tend to stick with the tetra test kit.