How do I lower the nitrate/nitrite levels in my aquarium?

Question

I have 4 tropical fish in a 10 gallon tank. My nitrate and nitrite levels are much higher then normal. How do I lower them?

Answer 1

Assuming you dont have one you might want to invest in a good protien skimmer to help with the breakdown of the waste in the tank. Also you may want to do a 10% water change on it also. This will help lower them. And perform a 10% water change on a weekly basis as this will help keep them low. Moving to a larger tank may be necessary also.

Answer 2

You have a lot of different options so far, but I'll put in my two cents worth here as well.

Nitrate will build up in a tank, but nitrite should only be present in a few conditions. The most common is when your tank is new and still cycling (building up enough bacteria to convert the ammonia and nitrite present into nitrate, which is the end product of the conversion). This should only last 3-6 weeks from the time you set up the tank. It can recur if you use an antibiotic to medicate your fish, because antibiotics don't distinguish between good and bad bacteria - all are killed, so the tank must go through another cycling period to establish the "good" bacteria. If neither of these fits your situation, the problem will be related to stocking (too many/large of fish for the tank size), overfeeding, or inadequate tank maintenance (water changes).

A 10 gallon tank isn't that large, and depending on the type of fish you're keeping, a 10 gallon may not be large enough for them as adults. The fish as you see them in stores are typically only a few months old. A group of inch and a half goldfish, for example, may be okay in a 10 gallon for a few months, but these will eventually grow to be 4 to 18 inches long at maturity (depending on the variety). By that time, they'll need 10-20 gallons EACH. So what may have been okay for your fish when you first bought them may not be as the fish grow.

Feeding should be limited to what the fish can finish in 2-3 minutes twice a day, and any left in the tank after that time should be netted or siphoned out of the tank. Decomposing food will also raise ammonia/nitrite/nitrate levels. The exception I'd make is for nocturnal fish, where I'd revome excess food the following morning.

As far as cleaning/water changes, I suggest changing 25% of the water at least on a weekly basis. A gravel vacuum should be used as the method of water removal rather than "dipping" the water out, since the siphon will remove the accumulated wastes in the gravel (which eventually decompose and add to the nutrient content in the tank). If your values are much above 1.0 ppm for nitrite and 40ppm for nitrate, you may want to do a few changes over consecutive days to bring the level down sooner.

One other possibility I didn't mention was the use of a nitrigen binding water conditioner. These are the types which make ammonia, nitrite, and nitrate "safe" for your fish by "detoxifying" them. While they may be "detoxified" they're still present in your tank, and they still show up in your water tests. Using these products also doesn't seem to make them as "available" to tank bacteria as the products claim. It's best to use conditioners that remove just the chlorine/chloramine as your water provider uses to treat the water supply.

Protein skimmer will help remove organics in the water in saltwater, but they're ineffective in freshwater, since the small size of the bubbles produced in saltwater can't be duplicated in freshwater. You don't mention that your tank is saltwater, and if it isn't I'd pass on that option.

Adding tank bacteria may help if your tank is in the cycling (or recycling) process. You can get this through purchased products, or by using an old piece of filter media or a handful of gravel from an established tank (just be sure the tank is free of diseases, parasites, and algae/snail problems - you don't want to solve one problem by introducing another!). You can add either of the "seeding materials" to your filter, or place them in the tank. Increasing the tank temperature will also encourage the bacteria to reproduce more quickly, shortening your cycling time.

There are a few occassions that I wouldn't suggest adding bacteria. That's if your tank is already cycled (beyond 2 months running or after antibiotic use). If the problem exists because your fish are growing, are overcrowded, or you're overfeeding, your tank probably already has the amount of bacteria it can support. Adding more won't be a solution. If anything, excess bacteria also die and add to the amount of ammonia, nitrite, and nitrate in the tank.

Answer 3

Regular partial water changes will keep the nitrites/nitrates in check. In a 10 gallon tank, you'd want to siphon out 10-20% every two to three weeks. You could also add live plants to your tank (make sure they can live under the lighting you're using). They will absorb nitrates. Java moss can tolerate low lighting fairly well and live plants will certainly benefit the fish in your tank.

Answer 4

i agree that water changes are the best way.Do a largish change to start with 30-40% then 10% per week after that.If you have high nitrites then it sounds like your tank is still cycling or is having a mini cycle which is a whole new problem altogether.Nitrates on the other hand will build up slowly and will have to be removed with regular water changes.If you use bio balls in your system remove them.They are nitrate factories.

Answer 5

I don't agree that live bacteria products are "lazy." They can be, but at least this is a beneficial lazy vs. products that claim to eliminate ammonia. Now these are lazy and detrimental. Anyway, if live bacteria is used correctly, it can be a lifesaver. Regardless, for emergencies where you have deadly spikes, live bacteria is a great product as long as you buy it from a reputable fish store whom you know keeps fresh product and keeps it well refrigerated. I, myself, prefer Bio-Spira. It has been a top-shelf quality product for me. This in combination with frequent water changes and testing will correct your high readings in about a week or so. Of course, this does depend on what 4 tropical fish you have in your 10 gallon tank. If they're guppies, platys, swordtails, mollies or other small fish, you'll be fine. If they're gouramis, angels, cichlids or other large fish, you may never be able to keep your water in healthy parameters.

Answer 6

The lazy (in my opinion... the BEST then... heheh) way is to add things like Cycle. It breaks down the stuff and works great. I use it. It may cloud the water but that's not a bad thing at ALL. It cears up in a day or two and it's just bacteria blooming.

Answer 7

Do a water change and add some antibiotics adn cleaners to the tank.

Answer 8

Do a partial water change. Add Cycle (I agree this is the best stuff ever). And make sure your filter is working properly.

Answer 9

1/4 water change every other day 3 times :)
this will take care of it