Natural NITRATES too high?

[crstlblu2002]

I'm in the US and I have 4 various tanks (55 gallon freshwater African Cichlid tank with approx 18 juvenile to adult sized fish, 20 Gallon brackish puffer fish tank with a green spotted puffer and a figure 8 puffer, 5 gallon freshwater tank of fry, and an almost cycled 30 gallon freshwater tank with no fish... getting that one ready for pirahnas). My question is this- my NORMAL nitrAtes are 40-80 ppm. I cant ever get them to stay lower no matter how many water changes I do. I tried changing 75% of the water on my 55 gallon once and it got down to about 20ppm but by the next day it was back up to 40-80ppm. Even my almost cycled tank with no fish in it went from an initial reading of 5-10ppm to 40ppm in 2 weeks. Straight from the tap my water runs 5-10ppm. I am using the API master freshwater test kit. I tried seachem's denitrate remover which didnt work. I dont overfeed (in fact i tend to UNDER feed). The 55 gallon tanks has been running since November and the other tanks followed in the proceeding months. I do water changes weekly from 20-50%. Does anyone else have the same problem? The LFS says 40-80ppm is not harmfull but I seem to have made it my mission to get them down as low as I can. Is this leven really harmless to the fish? I would like to change over my brackish to full saltwater next year but I'm worried that those nitrAte levels will be too high for salt water fish.

[shrimpgirl]

Hi. My tap water tests 40ppm on average. As it goes in at that level I cannot get it lower than that without using RO water. My lfs is just down the road so they have the same water as us. I have had to accept this level as I am disabled and cannot cart around RO water. My fish are all well as are the lifers at the lfs.

[m_attt]

fish will fine, planted tanks dosing dry salts will have levels 3 maybe 4x that.

[Carylnz]

My nitrates are the same as yours from the tap too. Never had a problem.

[ady]

same here.....natural level of 40....all fish are fine...

dont sweat it too much,we all want perfect water for our fishes,but sometimes it cant be acheived.fish should be used to it

i've got anubias,mini anubias and amazon swords planted in my tank,this helps the levels no doubt..