Strange water

[Swampman]

Hi I have a 20 gal tank that has been up for 4 years. right now there is only a horse face loach and a red dwarf place. Lots of plants. My Nitrate is very high. Amonia is goo and so is nitrites. Can't figure out why the Nitrates are so high. There is double hang on back filters. Water is changed 7-10 days. I was changing it every 5 days to see if I can get it lower. did not work. this has been going on since May 2023. I thought it was because I take the filter out a squeeze stout a bit. So I stopped doing that. Anyone else have problems such like this?

 

[Aiken Drum]

What is the nitrate precisely? Is there a reason you are worried about it?

You say ammonia and nitrite are good. What are they precisely?

What test kit are you using? Have you checked the expiry date?

High nitrate is usually a result of high ammonia cycling to nitrate. You dont have a lot of bioload for the size of your tank, so look for other sources. Are you overfeeding? Do you have a nutrient rich substrate? Is there ammonia (chloramine) in your tap water? Are the plants dying and being left in the tank to decompose?

Another cause could be high nitrate in your tap water. Here in the UK 50ppm of nitrate is an allowable level. It would be impossible to have low nitrate with such water unless you took measures to lower it. What is your tap water parameters?

Have you had the nitrate double checked with a different test kit or had a fish store check it. Nitrate tests are notoriously inaccurate, the test kit goes bad and becomes inaccurate quicker than tests for other parameters. Even professional testing is difficult to get accurate test results for nitrate. So many things can cause falsely high results. Nitrite for instance.

 

[Colin_T]

How much water do you change when you do a water change?
Do you gravel clean the substrate when you do a water change?

How often and how do you clean the filter?

 

[angiemike6]

I also have a problem with my tap water where nitrates measured at 40 ppm. My nitrate level is difficult to tell on a test kit as the colour I believe to be partly subjective. My ammonia is 0, nitrites 0, PH 7.6, GH 16, KH 6 and nitrates 40/80 ppm. I do 30/50% water changes every week, but cannot of course bring nitrates down below that of the tap water. Having said all that my tank is mature, I do not lose fish nor do they get ill. Most of my fish are more than 5 years old.