why is there nitrate in the water? or is that the tank water you are testing. there shoud be no nitrate in the tap water and absolutlely none in the filtered water.

try, straight RO water left for 24hrs.

I dont have any idea why i have nitrate in that water. Is only Ro plus tapwater after 24 ours or more. Something is strage here... Normaly the nitrate should be 0 if I'm right. What do you think? I know that the quality of the water is bad in this are where I live. I will go right now to see what is the level of the nitrate in the RO water. Thank you again and again and again

there should be no nitrate in your tap water, indicates organic matter

test the tap water to ensure it not coming from your filter for some odd reason.

also, how much water has passed through it to date? Mine said to flush it with about 100litres before using the water

Uf, for my system they sayed something to wash the filters with a few liters befor starting the use of the RO system. I did as they sayed. I asked a friend from Constanta which is near my city. He sayed 'heheh why do you belive that 90% of peoples are drinking mineral water?'
What do you think about this. Maybe after I will come back from my voyage I will buy some filters for my tap water. My friend told my also to insert a filter inside the drum where I have the exchange water for my aquarium to reduce the NO3. What do you think?? I already inerted a sponge filter inside my RO water and after a few days I will make some new tests to see if I have any result. Cheers!!!

sponge filter wont remove nitrate

biological filtration turns ammonia to nitrate and water changes remove nitrate from the tank.

did you test the tap water?

Yes I've already tested the tap water and the the parameters are same, about 25 mg/l.

0.5 difference is roughly 5 times difference for the fishes, since pH changes logarithmically.

Thank you. I will take this in consideration!!! Curently i'm gone a few days, maybe I will get some small long fins from a friend since I'm in Bucharest now. Cheers!!!

I am shocked by the 25 mg/l level!

I have two taps (kitchen and garden) and even water from the garden - which is not treated as well as the drinking water - has 0 mg/l.

I will try to use other test from other brand. The test which I used it is TETRA. Do you recomand other brand?? I also sayed that is strange.
I dont know what to say or what to do. If the water still have this parameters after other tests what do you recomand to do to reduce the nitrate??? Thanks!!!

I have JBL and Sera stripes and liquid Sera for No2, NO3, GH, kH and pH.
All proved to be reliable giving accurate results.