How to lower nitrate?

[Polly]

Hey!! I was told to use clearmec plus to lower my nitrate but its not working, can anyone help please? PH 7, 0 ammonia and nitrite, nitrate around 80? I have been using it for around 2 months.

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[aqua_holic]

Have you tried changing the water?

 

[Patty1980]

Big water change time. Don't know what that chemical is, but I only use Prime dechlorinator in my tank. Water changes control nitrates.

 

[Polly]

I do weekly water changes of at least 25% or more... its a 200L tank. And use prime with every water change. Everything else is normal except the nitrate. The fish shop owner said its not harmful to fish but i still got that clearmec stuff to lower it cuz that was what he recommended.

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[PNWaquarist]

I do weekly water changes of at least 25% or more... its a 200L tank. And use prime with every water change. Everything else is normal except the nitrate. The fish shop owner said its not harmful to fish but i still got that clearmec stuff to lower it cuz that was what he recommended.

I've never used that stuff, but am pretty sure it doesn't work. The fish shop owner likely sold it to you to make a few extra bucks. Typical.

The only safe and effective way to reduce nitrates is water changes. How heavily stocked is your tank? How much are you feeding?

Right now, I'd do 20-50% every-other-day water changes until that nitrate level gets down to 20 ppm or so. Then you can return to your usual water change routine. Your fish will likely not do well in 80 ppm nitrate indefinitely. Most species of tropical fish will be fine at < 40 ppm nitrates.

 

[Polly]

35 fish.....15 swords, 7neons, 1 ram, 1 baby bristlenose, 1 small redtailed shark, 5 sailfin mollies, 5 platies. Feed them 5 days a week. Enough flakes for them to eat in 30seconds and 5 small pellets. Also a cucumber or zucchini or something for the bristlenose

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[Polly]

All fish under a year old so they are not large

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[ScotJudd]

Just as a precaution check for nitrates in your source water (usually tap).
If it's low, under 10, then water change regularly to bring nitrates down. Plants can help a lot if your lighting allows.
I have a 200l with loads more fish than you but a shed load of plants. I still need to do 50% WC a week but may do it twice at 25% in a week. Nitrates sit at around 10-20.
80 is just not sustainable in the long term despite what your LFS said. Remember, dead fish = more sales!


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[Polly]

Will check my tap water when i get home!! I have a huge tendency to kill plants so have gone with plastic plants and a handful of java moss ( i even killed my cactus at home!)

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[CCXGT]

Might I recommend sticking a bag of Purigen somewhere in your filtration system?

I have undetectable Nitrate levels in a 240l with 20 Africans in it.


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[Polly]

Thanks!! will definitely check purigen out!!

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[PNWaquarist]

35 fish.....15 swords, 7neons, 1 ram, 1 baby bristlenose, 1 small redtailed shark, 5 sailfin mollies, 5 platies. Feed them 5 days a week. Enough flakes for them to eat in 30seconds and 5 small pellets. Also a cucumber or zucchini or something for the bristlenose

Wow, that is a really nice-looking tank! Sounds like you're not over-feeding and are feeding some variety as well.

That said, I strongly recommend that you knock the nitrates down to < 20 ppm. Rams are extremely sensitive fish and tend to not live long in high nitrates. Also, you're going to have to re-house that RT Shark. They get very aggressive when they get larger.

You may or may not also have problems keeping Neons and mollies in the same tank. Mollies like brackish water and Neons like soft water. It depends on the environments in which they were raised.

 

[Coyne]

Its time for "Fun with Math" or "Why 25% PWCs Aren't Enough".

Lets say that your aquarium nets 20ppm of nitrates a week. Your number will likely be different, but for the purpose of this example I'll use 20.

So, you have 20ppm nitrate and do a 25% PWC
20ppm - 25% = 15ppm nitrate

Assuming you have no nitrates in your tap water, you are now at 15ppm nitrate.

Now a week as gone by and the tank has generated another 20ppm nitrate.
15 + 20 = 35ppm nitrate

Time for the weekly 25% PWC
35ppm - 25% = 26ppm nitrate (Ive actually rounded DOWN here, so no complaining)

So 26ppm nitrate after the PWC, but a week (and another 20ppm) later, your at 46ppm nitrate. Time for a 25% PWC.

46ppm - 25% = 34ppm (again, I'm rounding down... its actually a little higher).
Another week goes by and now your at 54ppm nitrate.

Time for a 25% PWC.
54ppm - 25% = 40ppm (rounded down)

One week later and its at 60ppm nitrate.

As you can see, by only removing 25% of your water/nitrates every week, your total nitrates are going to slowly increase over time. I only went out 4 weeks and the nitrates went from 20ppm to 60ppm... that's triple!

You might say "But I only net 10ppm nitrate every week." That's great. It means that the process will take longer, but it will eventually increase to a level that you probably don't want.

You might say "I do 50% PWCs every week". Also great. But it's also just delaying the inevitable.

Your best case scenario is that you are netting 0ppm nitrate every week. This means that your plants (or whatever) are absorbing 100% of the nitrates produced every week. This is pretty tough to do, but if you can manage it then your nitrate problem is solved. I'd still recommend weekly PWCs though, since you'll want to keep your GH from slowly increasing from evaporation.

Your next best case scenario is that you do a 100% (or as close as you can get) PWC every once in a while. This lets you get rid of much of the excess nitrates as possible and allows you to start the equation over with a much lower starting number.
For example:
I do weekly 50% PWCs, but on the 4th week of the month I do one that's around 90%. I leave just enough water to cover the fish.

Be careful about doing such a large PWC when your nitrates have already reached a high number. Fish slowly get accustomed to the nitrates levels (this doesn't mean it's not unhealthy) and a sudden drop can shock the fish. Better to do several smaller daily PWCs until your nitrates are back down to a manageable level.

 

[PNWaquarist]

A tank that produces 20 ppm nitrates per week needs multiple WCs per week. Doing a 90-100% WC may be more stressful for your fish than higher-than-desired nitrate levels.


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[AlbinoShark53]

My nitrates were way up a while back because of over-feeding and not having enough time to clean really. Nothing I used worked and I finally got the time to do some major cleaning so I cleaned the rocks and, in the process replaced most of the water. Now my nitrates at a steady 20. You may have to do some cleaning and/or adjust your feeding habits. And the fact you have killed plants may be another factor. Nitrates are created when waste partials that aren't removed in time combine with chemicals in the water to create compounds that are harmful to the fish if there is too much (someone correct me if I'm wrong please!). So maybe take those factors into account. (Sorry if I'm thinking of something else and I'm wrong!)

 

[AlbinoShark53]

Hope I helped a little

 

[Coyne]

Admittedly I don't have anything to measure fish stress with, but my fish do not exhibit behaviors associated with being stressed after large PWCs nor do I have random sicknesses or deaths.
I can't think of anything in the water chemistry that would have a negative impact on the fishes' health if a large amount of water was exchanged using the same source water. KH, GH, pH and temp should all be comparable. If they're not, then that's a separate issue.

 

[PNWaquarist]

Admittedly I don't have anything to measure fish stress with, but my fish do not exhibit behaviors associated with being stressed after large PWCs nor do I have random sicknesses or deaths.
I can't think of anything in the water chemistry that would have a negative impact on the fishes' health if a large amount of water was exchanged using the same source water. KH, GH, pH and temp should all be comparable. If they're not, then that's a separate issue.

I'm sure that your system works fine for your fish, but it may not be applicable to everyone's stock. I would probably not do 90% WCs for "taller" fish such as angels or silver dollars, for example.

That said, I do agree that one very large water change every once in a while does a nice job of knocking back nitrates. I probably wouldn't exceed 70% in my tanks, but that's just me.

 

[aqua_holic]

I've forgotten I was draining a tank and had my severums lying in their sides to stay wet. I generally try to leave enough water that movement around the tank is not restricted.

 

[PNWaquarist]

I recall somebody posting a story about discus owners who do 100% WCs once a week. And it apparently works fine. Of course, discus are very intelligent and learn to trust their owners. I can't imagine that it would work well with a skittish fish like a silver dollar.