high nitrates - Tropical Fish Keeping - Aquarium fish care and resources
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post #1 of 8 Old 03-27-2012, 01:56 PM Thread Starter
high nitrates

hello im having high nitrates in both of my tanks one is a 46g bow front with a 11yo parrot fish, 1 dempsey maybe 5" long, and 2 fish i inherited a flowerhorn about 3" long and a yellow lab about 2.5" long.

the other is a 10gallon with a 13 or 14 yo red zebra he has recently got a crawfish companion. the kids thought it was cool so i got it. the red zebra is over the top aggressive but he dosent bother with the cray.

my big tank is recovering from ich at the moment and the nitrates are around 100. i have done 2 water changes one at 50% and one at 25%. they just seem to hold steady.

my 10gallon is disease free but also has high nitrates its about 100 too. i did a 50% water change a couple hours ago. i just checked the nitrates and it made no difference. my tap water comes up as 0 nitrates.

yestersday i put a pothos plant in the filter of the 10g tank to see if it helps. i plan on doing the same for the 46 but i was going to wait till after the ich medication has been cleared.

any ideas on what i should do? thanks you i appreciate the help!
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post #2 of 8 Old 03-27-2012, 02:28 PM
There are several things you can do. Fortunately you have zero nitrates in your tap water (my well water is very high in nitrates, so my approach has been different) so you should be able to bring nitrates down with several partial water changes. Don't go any more than 50% at a time.
We need to examine how your nitrates got so high. Have you slacked off on weekly water changes? over fed the fish? over stocked the tank?...

Other options for maintenance and nitrate reduction:
> Add plants, even floating plants will take in ammonia that won't convert to nitrates and they will use some nitrates as well.
> Be sure not to over feed...and I don't mean just uneaten food although that's a problem. Fish will over eat much like people and the more they eat, the more they poop. Obviously we want to feed our fish enough to be healthy, but we need to control their intake--->OUTPUT.
> Good tank and filter maintenance will help reduce nitrates. Including a periodic gravel vacuum to remove decaying waste. Often filters let go to long become nitrate factories so more frequent servicing pays dividends.
> Activated carbon, although frowned on by many has been used for decades to purify water. In addition to adsorbing a wide range of impurities, it will also adsorb nitrogenous compounds thereby reducing nitrates.

For more serious address:
> Products like Seachem Purigen, a rechargeable synthetic resin is an organic scavenger that adsorbs organics in solution before ammonia conversion, thus reducing nitrites and nitrates.
> Products like Fluval Lab Series Nitrate Remover and API's Nitra Zorb are synthetic resins that adsorb nitrates.

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post #3 of 8 Old 03-27-2012, 04:41 PM Thread Starter
thank you for the reply, last night i read the entire eight pages on your thread about the add on filter you made and am considering something similar.

to answer the question of why well honestly i just kinda neglected the tank. im quite sure ive been overfeeding for years. i dont think im overstocked but i dont think im far from it. my girlfriend loved my tank and she decided to get one herself. i found here a killer deal on a used 55 with absolutly everything. i got that up and running it it looks really nice. doing this has kinda got me back into fish again.

should i do a water change everyday or more to get the nitrate down?

unfortunatly my big tank got ich and i didnt notice it due to total negligance on my part :( i lost 2 fish because of it. the fish look good now but im still weary of putting the carbon back in my filter. i really wanna make sure the ich is dead so it dosent come back.
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post #4 of 8 Old 03-27-2012, 06:57 PM
It's almost odd that on this and other forums there are those that believe that even high nitrates of 100ppm+ are nothing to worry about. I am convinced that over time, high nitrates are lethal. And since fresh water in nature does not have nitrates (or levels are too low to measure) all the more reson to get them out of our aquariums.

To be honest I really developed the DIY bio-nitrate filter because it was clear I could no longer use my well water and continue 50% weekly water changes. My thinking is that if I can keep nitrates very low AND otherwise increase filtration, I could reduce the frequency/volume of water changes whether I buy or make DI water. I think DI water will be my direction. Actually the well water nitrate discovery caused me to seriously rethink filtration and water changes. (but I'll bet you got that from the other thread )

You have a clear advantage of good, low/no nitrate tap water. Once you get your nitrates under control AND change your bad ways and do regular water changes, you should be good!

Now you'd think that if you did a 50% water change w/zero nitrate water, you'd chop your tank nitrates in half and after a few of these, they'd be gone. It didn't work for me. I did several 15-20g water changes on my 60g tank over a week or so and I couldn't get nitrates to come down at all. I resorted to using Fluval Nitrate Remover to get them down. Nitrates in my tank have now been stable for nearly two weeks at 10ppm. I can't say this is the filter as at the start of this I also added 3 bunches of anacharis floating plants that are doing well and I'm sure help with ammonia. I'm hoping with the filter to get to 5ppm or less nitrates, but think I'll need some patience for that.

I'd say you can try a 50% partial water change daily or every other day and see what happens with your nitrates. If I was you, on the first one, I'd do an aggressive gravel vacuum and service your filter (shut down any nitrate factories).
If that doesn't work, I'd do a total tear down/clean-up, taking care to preserve the substrate and filter media with moisture.

Keep us posted.


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Last edited by AbbeysDad; 03-27-2012 at 07:00 PM.
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post #5 of 8 Old 03-27-2012, 07:29 PM Thread Starter
well i went and did a good gravel vacuuming and changed about 1/3 of the water. i still didnt put the carbon back in the filter. i may put one more dose of ich medacine in just for good measure. i used two different test tubes to do a before and after test and they look exactly the same :(
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post #6 of 8 Old 03-27-2012, 07:34 PM
Yep, choppin down the nitrate redwood can be tough.

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post #7 of 8 Old 03-27-2012, 07:35 PM Thread Starter
i forgt to mention i just dumped out the filter water and refilled it with tank water. it wasnt nasty but there was a little crap in there.
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post #8 of 8 Old 03-28-2012, 11:35 AM
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I'll just reinforce what AbbeysDad has stated. With zero nitrates in the source water (tap here), you should never see high nitrates in an aquarium. And this means they should be below 20ppm. With live plants they will be much lower than that (assuming the tank is biologically balanced of course), but without plants this is the number to stay below. And the way to do this is not overstocking the tank, not overfeeding, and weekly partial water changes. Every week, without fail, change at least 50% of the volume. I estimate this number on your fish load; large fish produce more waste. This is adequate to maintain low nitrates if the tank is balanced.

Byron Hosking, BMus, MA
Vancouver, BC, Canada

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian. [unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]
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