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Hi, I'm new to this site. I'm an Aussie and have a 180L tank which I have had running on 2 Fluval 204s for 3 months. I have 3 x 6" royal farowellas, 1 normal farowella, 1 x 6" hoplo, 2 x 4" silver sharks, 2 x 2" upside down catfish, 1 feather fin synodontis, 3 x 3" clown loaches, 2 x 1" danios and 5 various corydoras caties. I do weekly water changes with treated tap water. I feed a variety of bottom feeder foods sparingly (I think) twice a day. I maintain my filters regularly to maintain the flow. THe ammonia and nitrite are 0 but the nitrate is around 40ppm. I have just today removed the sharks and 2 clown loaches to lighten the load. I'm concerned this is going to stress the fish and would like any sugestions on how I can rectify this. I also have 2 x 3 ft tanks and these are running w/o problems. Over here in Oz the price of Sth Am fish is quite high so I don't want to loose any. Please help.

My L260 tank is around 30ppm, and they do fine. My L104 tank is up around 50ppm, and they are eating well and prospering. My mbuna tank is even higher, and they breed like rabbits. I do everything you do to, the nitrates are just high. But it doesn't bother the fish, so it doesn't bother me. I would do at least 3 straight weeks were you do a deep cleaning of your substrate, this should help alot.

Just do more frequent water changes. I keep goldfish and change 50% each week.

I also use seachem purigen - 2 pouches each in my 50g and 40g tanks. They help a lot.

You could check your tap water for nitrates, too. Around here the tap water contains nitrates after it rains. Yours may too, so avoid water changes after a storm. Good luck!!

Andy

Nitrate levels begin stressing fish at 100 ppm and become toxic to most fish at around 140-150 ppm. A typical community tank can ride at about 50 ppm although hobbyists should shoot for less than 25 ppm. Planted aquaria and breeding tanks should try to stay below 10 ppm.

How to reduce nitrates:
1) As stated above, frequent large water changes. Check your tap water first though. Tap water can have up to 40 ppm nitrates. If your tap has elevated nitrates, you will need an RO filter or different water source to get them below what is already in the tap water. Many people recommend a series of daily 20 percent water changes to get rid of Old Tank Syndrome (i.e. accumulated nitrates). I would go straight to a series of 40-50 percent water changes every day for 3-4 days to get things where I wanted them.
2) Feed less: Except for fry, no fish needs two feedings a day. I know many succesful hobbyists that only feed once every other day. My schedule is 5 days of food (one feeding per day) and one day off.
3) Other than water changes, plants are about the only way to reduce nitrates.
4) Keep all the filtration equipment in tip top shape.
Hope this helps,
-Shane

Thanks heaps for helpful advice. The tank is heavily planted and our local water has 0 nitrate. So I've done numerous water changes and I always keep my filters in tip top running order.
Have to celebrate the discovery today of bristle-nose fry that look a week or so old in one 3 ft tank.

If your tapwater has no nitrates, them all you have to do is up your water change frequency and volume.

try 40% twice a week.

As Shane says, cutting down a bit on food will help a lot too.

Depending on the time of year, my tapwater can come with nitrates. I use a test kit on the tapwater. We don't drink it. Like clockwork, if the test comes back with nitrates, the next day, the water smells like chlorine out of the tap.(The town treats the water.)

bronzefry wrote:Depending on the time of year, my tapwater can come with nitrates. I use a test kit on the tapwater. We don't drink it. Like clockwork, if the test comes back with nitrates, the next day, the water smells like chlorine out of the tap.(The town treats the water.)

Hmm. I wonder why there's a correlation. I don't see how it would relate to each other, really. [Unless you otherwise have a high level of ammonia/nitrite, in which case the chlorine would kill off the nitro-bacteria, but I seriously doubt that either the nitrite or ammonia levels are high enough to cause even the more sensitive of nitrate tests to show anything. That would certainly be bad, if it was the case...]

What sort of levels of nitrate do you get in the water. Also, does your water usually come from surface or underground source?

If it's a surface source, a large amount of rain could wash fertilizers and such into the water, which would increase the nitrate.

If it's underground water, I would expect the nitrate to be relatively stable.

--
Mats

It's well water, but the wells are running dangerously low. There are too many new mega-houses being built without making accomodations for infrastructure. The town was established in the 1600's. The wells haven't changed much since. When nitrates show up in the water, it tends to come up on the aquarium tests between 20-40 ppm. The higher readings are when we get the chlorine smell. We get town water reports once a year, delivered by mail. It lists the water quality. Nitrates are listed as a problem, along with silicates and e.coli. Flouride is also added. Luckily, the readings have been under 10 ppm for about 2 weeks now. Summertime is the worst. Besides the RO, I don't know what else to do. Do you do anything in particular to you water in Mexico City, Shane?

Nitrates - the bane of fishkeeping.

Despite water changes, which we all do (or should do), nitrate readings are appaling, and in high pH tanks, can be deadly. Why? Where does all this seemingly sourceless nitrate coming from?

High Nitrate readings, when absent in water and food sources and not completly diluted with water changes, is the waste product of the bacteria we all depend on to metabolize the nitrogen complex waste products living things produce (you, me, our fish). High nitrate readings are an attest to the efficiency of bacteria to reduce very toxic ammonia to less toxic nitrite then to least toxic nitrate. What we are missing it the next step, reducing it a step further to what we all breath - nitrogen gas (we breath 21 percent oxygen, 70 percent nitrogen).

Higher plants DO metabolize SOME of the nitrate available for that gas; in fact a mature, stable freshwater heavily planted tank should always have less than 5 ppm nitrate if sensibly maintained. Mine hover around 2 or 3 ppm.

Marine reef hobbyists have difficulty keeping animals like anenomes because of the gap in the nitrogen cycle. Five ppm will stress and shortly kill one, as in nature nitrate is nearly absent on the reef.

The scope of this forum isn't such that I can go into great detail about nitrate reduction, but I'll give the salient points.

Several years ago it was discovered that bacteria that exist in low 02 levels (about 0.02 to .2 ppm) reduce nitrate to elemental nitrogen gas, completing the cycle and stabilizing the aquarium, keeping nitrate exceedingly low and eliminating nitrate spikes.

Thus, the plenum method was born. A plenum is a empty space beneath the substratum where low O2 water exists. The space has been dubbed the anoxic zone. Google plenum for more information on this method. PM me for appropriate literature.

Planted tank folks, myself included, find difficulty with the plenum method as the roots of our plants intrude into the anoxic zone, nullifying the effect. I am currently investigating using a remote plenum for planted tanks (whether its worth it or not). Right now I'm testing a commerical product that was recommended to me for canister filters.

Another method is sulfer denitrafication, but the jury is still out on it (there are efflufient concerns) and it will be some time until it trickles down to common use among freshwater folk.

The upshot of all this is that high nitrate and high nitrate spikes during seasonal variables, etc. CAN be eliminated or greatly reduced in freshwater and marine aquaria.

There is hope.

Dave