Constantly High Nitrates

**jgranata13** · 01-02-2013, 08:34 PM

Hi everyone,

I seem to be having a nitrate "problem". It's not a problem in the sense that it will do harm to my fish, just that they seem to be accumulating faster than they should. My tank is 3 years old.

I have a 37 gallon tank with an Aquaclear 50 filter. I have two gold gourami, a platinum angelfish, a sunburst platy, two black tetras, five serpae tetras and two corys. I don't think I'm overstocked (am I wrong?), but I know that I'm definitely at the upper limit. I feed once a day and hardly any food makes it to the bottom.

Generally, my nitrates get high enough within a week that I do about 75% water changes every week to bring them down (they are usually around 20ppm by the end of the week).

The other thing is that the nitrate levels seem not to scale down appropriately when I change water. For example, if you do a 50% water change, you would expect the new nitrate level to be half of that before the water change. However, I've been testing my water before and after the changes recently, and the levels didn't scale down as much as they should have (going only as low as 10ppm after the 75% change). The problem is that my tap water has no nitrates in it and I KNOW that the nitrates in my tank can't be building up that fast in the 30 minutes that it takes me to do a water change.

Also, the angelfish was a recent addition (I got it less than a week ago) but my nitrates have been like this since before I got it and I doubt very much that my tank was overstocked before I got the angelfish.

What could possibly be the problem? All suggestions and/or remedies welcome. Thanks in advance!

**KingFisher** · 01-02-2013, 08:41 PM

That's a perfectly normal amount of nitrates to build up in a week. The reason your nitrates seem to be a bit higher than they should after that size waterchange is most likely due to the new water going in stirring up the substrate a bit and causing them to release a little more. Still, those levels are perfectly fine.

**jgranata13** · 01-02-2013, 08:48 PM

Really? I've read from a bunch of sources that they shouldn't be above 5ppm.

**cichlids209** · 01-02-2013, 08:49 PM

yea 20 is not bad at the end of the week before your water change, but i would still get another filter. An ac30 would be perfect in addition to your ac50 especially since your tank is pretty stocked

**cichlids209** · 01-02-2013, 08:51 PM

Originally Posted by jgranata13

Really? I've read from a bunch of sources that they shouldn't be above 5ppm.

the lower the better but 20 is about the highest you want to have at the end of the week before your water change you could also do 2 50-70 % wc a week and see if that lowers your trates is the filter media dirty i had the same prob with mine and cleaned the sponges and they dropped

**KingFisher** · 01-02-2013, 08:51 PM

Originally Posted by jgranata13

Really? I've read from a bunch of sources that they shouldn't be above 5ppm.

Can you cite these sources? I've never seen that anywhere before.

**KevinVA** · 01-02-2013, 08:52 PM

When's the last time you cleaned out your filter?

KF is right, though. 10-20ppm is within a healthy range. As long as you keep up your regular schedule of 50% weekly water changes, you'll be fine.

**Goes to 11!** · 01-02-2013, 08:53 PM

Two things I would add to that.

1. I think you are under filtered a bit as that filter is good for a 25g tank tops IMO.

2. When is the last time you cleaned your sponges? I mean REALLY cleaned them. If you have ceramic bio media as well as sponges here is something you can do that may help.

If you have a bucket put some dechlorinated water in it and set your bio-media in there and set it off to the side.

Now, Take your sponges and rinse them under the tub faucet with warm water until they run clear.
Squish them in the dechlor water a few times and you are ready to put it all back in. The funkyness you saw running down the tub drain was not helping your TrAte issue any.

I will leave the stocking advice that you undoubtedly have coming to someone else.

**jgranata13** · 01-02-2013, 09:04 PM

I clean out my filter usually every six weeks (this is when it starts to get dirty and the flow becomes impeded. I rinse it in buckets of tap water until all the media looks as new as it can possibly get.

I don't exactly remember where I found the 5ppm stat because I've been doing a lot of reading recently, but I know that there were forums, YouTube videos and online articles in there.

EDIT: I meant to say tank water; I rinse the filter media in tank water, not tap water.

**ryann** · 01-02-2013, 09:04 PM

+1 to all the above

As for the stockings issues...

2 gouramis in a tank that size seems dangerous. I think one will most likely kill the other and you should try to rehome 1 of them.

Tetras need to be in schools. You should get 10+ of one of your tetras to make it an adequate size school and then rehome the other kind of tetra. I would not put 2 schools of tetra in a tank that size.

Corys also need to be in schools. You should have at least 7 preferably 12+ corys.

Your stocking has some major issues right now and I can't imagine your fish are too happy. Schooling fish should have at least 6 but to make their behavior become more natural you should have over 10. Once you add to your schools your tank should look better too instead of a couple of this, a couple of that in there.

EDIT: I see you added another post and when you say your rinse your filter sponges in tap water I hope you use dechlorinated tap water or else it will kill your BB. I agree that you should get more filtration and that cleaning might help it but staying under 5ppm is not necessary, 20ppm or lower is fine.