I have a 100g tank with a 10-12 inch jaguar, an oscar about 8-9 inches, a 7in JD and a small frontosa bout 4 inches and a 7-8 inch plec. I know this is overstocked when they are full sized but i think it is ok at the moment. The problem is my oscar got 3 small holes that are HITH. He got this because my last nitrate tester was giving false readings and the nitrates were a lot higher than it was saying

I have reduced the feeding and have been doing 2 50% water changes a week. This has been going on for 2 months now and the HITH isnt getting worse. I have been unable to get my nitrates below 20. On the old tester my tap water was 10 and on the new one it is 20

So to clear up the matter of which tester was right I decided to get my water tested. You phone your water company up and they ask what you want tested, you arrange a time and someone comes out and takes some samples of your water (it takes about 10 mins). It is a free service (in the uk)

My tap water comes with a nitrate of 22.8. The max safe level is 50 (according to the blurb 50 is the level you can get problems). So it looks like i might have to live with the minor HITH because it will be impossible to get the nitrates below 20. Hopefully it will get better in time

I would recommend everyone to get their water tested. Then you test your tap water every month or two and you will know whether your tester is working well (it should match the water companies result) and you wont end up with problems like me

Very good post, I have made it a sticky so it stays at the top, I think people will benefit from knowing this type of information. Thankfully, there isn't any nitrate in my tap water. I do a sizeable water change every two weeks on the 300 gallon tank and the nitrate is normally between 30 and 40 ppm. At the moment, it is no higher than 20 ppm when doing a weekly water change on the 125 gallon tank.

after reading this post i immediatly pulled out my test kit and tested my tap water for nitrates. happily for me it came back with a reading of 0.
but i was wondering if your tap water has a nitrate reading would using an r o system eliminate this? i know that r o system remove some of the minerals that are needed but would a mixture of regular and r o water help in lowering the nitrate readings? just a thought.

I actually use an RO system for my discus tank. It is a basic one but because i live in a hard water area it takes 2 days to 3/4 fill a dustbin sized container. The nitrates come out about 5. I then mix it 3 RO to 1 tap water when refilling my discus tank. My girlfriend has got used to the bin in our kitchen for 4 days a week (2 20% water changes)

A RO machine required to do a 50% water change on my 100g tank would cost loads and i would need a much bigger container to collect it in. Not sure if the g/friend would put up with a huge container in the kitchen!!! Either that or put the container in the loft with piping to connect an outlet downstairs, a major pain.

A word about RO machines. Be wary of these if you are on a water meter (thankfully i am not). For every gallon of good water, about 3 gallons is waste so it can be expensive. I live in a hard water area, in a soft water area you will get a better proportion of good water and less waste, but it will still be expensive

agree, great post.. i found out about nitrates in tap water about a 1yr after getting my 1st oscar(to late for him) . now 5yrs down the line i filter all tap water with a nitragon as i am on a tap meter and do a 50 gallon water change a wk and sometime twice a wk. i also found that sometimes my tap water reads 10% nitrates other times higher! nitragon are cheap, work faster (all water is used and not a %)and takes me a day to fill a 50gallon drum.... anyone with a better system for tap meters let me know.PS if u have 20% nitrates from tap u could lower it to about 5% the way i just metioned.Cheers

i just tested my water. its at 5ppm nitrates.