How do I lower the nitrate levels in my fish tank?

Question

I'm a new entrant to the wonders of the world of aquariums. I've just set up my tank and had it running with plants and gravel in it for the last three weeks. I was told by the aquarium shop that I needed to leave the water for two weeks before adding fish - which I have done - yet when I tested the nitrate levels yesterday, they were still way too high. I've had the filter buzzing away for the last three weeks and have added the suggested liquids to the water. So.... I'm pretty confused as to what I now need to do in order to get the nitrate levels down. Please help!!!

Answer 1

Good for you that you have taken the time to set up your tank properly. The beneficial bacteria in your tank develops in stages as your tank spikes first in ammonia, then in nitrites, then in nitrates. Fortunately, you are at the final stage of bacterial development and your tank is almost ready, but you should have been changing around 25% of the water weekly even without fish. Start now, and the nitrates will go down. As soon as they reach normal levels you are set to buy your fish.
A

Answer 2

Filters do not remove nitrates, nitrites or ammonia. If you have carbon in it, it will help remove the bad smell along with floating debris such as fish poo and uneaten food.

Nitrates are the third step in the 3-4 week nitrogen cycle that all new tanks must go through. They do not even start this cycle until fish are present.

You should only start with 2-3 fish for the first couple weeks and then add new fish very slowly so you don't cause an ammonia spike with too much added waste from a lot of new fish. The beneficial bacteria build very slowly, but are very necessary to an aquarium.

You must do regular (weekly) partial (25-30%) water changes starting now for as long as you own your aquarium. Chemical additives are unnecessary if you do your water changes religiously!

If the levels are dangerously high right now, do a 40% change right away and 30% every other day until the levels drop to 0 or close to it. Then you can switch to the weekly schedule.

I have 23 tanks and don't use any chemicals other than DeChlor when I do my weekly water changes (yes, on all of them). Some, that have babies in them, I do every 4th day.

Answer 3

Actually the point of cycling a tank is to get the bacteria that converts ammonia to nitrites, and nitrite to nitrate living in your tank in large numbers. (Nitrates are much, much less toxic.) You'll need to replace water to remove nitrates. Generally this is done using a cheap gravel vacuum to remove 10% of the water per week. In this case as you don't have any fish just remove 1/2 the water. 4 hours. Retest the water. Repeat until the levels of nitrates are lower than 10 ppm.


PS- It sounds like your tank is ready for fish. Once you nitrates are good you can start adding 1-2 fish per 10 gallons a week.

Answer 4

Nitrates will always be present in an established fresh water tank unless it is heavily planted with a very light bio-load. Nitrates are the end product of fish waste and decomposing organics.

Water changes are the most effective way of lowering nitrate levels (if your nitrate is 100ppm and you change out 30% your nitrate will be reduced to 70ppm).

Make an effort to keep nitrates below 40ppm. You should performing at least 25% water changes 2 to 4 times a month to control nitrates. Large bio-loads mean larger percentages of water changed out and/or increased water change frequency.

Plants lower nitrates to some degree.

Answer 5

Did you add any kind of ammonia source to start the tank cycle? If not, I'm guessing the nitrates are from your tap water/water source. Just setting up the tank and letting it run for 2 weeks, with nothing to kick start the cycle, won't cycle the tank. You can test your tap water/water source with a test kit to see what the nitrate level is. But, to answer your question, weekly water changes are the best way to keep your levels down and in check.
Do a search on these forums for fishless cycling, and cycling a fish tank.

http://www.aquariumboard.com/forums/home.php

http://www.aquariacentral.com/

Answer 6

NitrAtes aren't anywhere near as toxic as nitrIte and ammonia. If you don't have nitrIte in the water and aren't treating for illness, there's no reason to have salt in the tank. The only reliable way to get the concentration of nitrAtes down is through water changes (dilution is the solution to pollution). The point of weekly water changes is to prevent nitrate from building up too much. Try to keep it under 40 ppm. If you have nitrate in your tap water, get a lot of fast-growing plants to help combat it.

Good for you for cycling your tank before adding fish. :)

Answer 7

How high is your nitrates? How many parts per million (ppm)?Short term solution is to change water regularly but remember to maintain your water salinity. The salt gives relief from high nitrates and nitrites. For long term solution, you gotta have to have some aquatic plants which are salt resistant. Not many plants can resist 0.3% salinity. Some plants like duckweed or arrowhead comes to mind.
Having a waterfall may help in dispersing some nitrates in gaseous form. Maybe you can modify the return spout to drop the water high back to the aquarium but mind the splash. This increase in turbulence can help a bit in pumping a bit of O2 in the water. If your filtration system is fairly new, the increase in nitrates is quite understandable as your system needs time to mature. If you want to speed up maturing your filtration system, I would suggest you take some filtration medium from an established system and put it in your filter to speed up the propagation of the biological bacteria. But careful because you might introduce unwanted pathogens as well.

Answer 8

I would not recommend any chemicals except declorinator just do small frequent water changes every few days for about a week or so then get it checked again

Answer 9

Go to your pet store and get a water tester kit, it has ph up and ph down powders in it you can use yourself to neutralise the water, and then use the test tube to test the water, easy done your self at home, is comes with instructions, it should only cost a few $$.

Answer 10

They make stuff to lower these levels.
Go to a PET store.......Not wally world & ask for help.