Hi,

Was wondering if anyone might be able to shed some light on a problem i am having.

So, in our back garden we have a borehole and i use this water to fill a 200 litre water tank which i then use to trickle in to my pond, so every day i turn the borehole pump on and fill up the water tank then leave it to empty over the next 24 hours.

The water coming out of the borehole is as follows

NH4: 0
NO2: 0
KH: 210
GH: 350
PH: 7.35
PO4: 0.23
TDS: 288

I don't have any Nitrate reagents left so haven't test this recently but i seem to remember it being around 40ppm.

Now the problem i am having is i have 0 nitrite going into the tank, however the water coming out of the tank does contain nitrite, i tested it last night and the nitrite coming out of the tank was at 0.25.

Would anyone have any idea what might be causing this? I have tested the water coming out of the borehole many time and am 100% sure it is 0.

The water tank itself is stored with my pond inside a polytunnel, the air temperature can easily get to over 40 degrees in there, is there a possibility that nitrate can convert to nitrite under certain circumstances?

If anyone has any ideas or suggestions i would love to hear them
Adam