neverending nitrate problem

[moraym]

On a 40g Breeder with two Millenium 3000 filters and almost 70 lbs of LR.
Tank has been set up for a year and a half and nitrates have ALWAYS been a problem. For as long as I can remember I cannot get my nitrates below 80-160 ppm. I have a lot of tanks with no problems, but this one is insane. I have done a 20% water change EVERY DAY for 10 days, with hardly an impact. I added a purigen bag and it went from white to dark brown in a matter of a week.
Though a long time ago it was due to things getting caught in substrate, so I added a couple sand sifting stars, and an engineer goby that is now 9 inches long and really stirs up the bottom for me.
The nitrates haven't caused much death, as I've had fish that are now approaching a year and a half old, although it does cause me to not be comfortable adding new fish, and it obviously causes there to be no way to add corals and also causes my fish's colors to dull.
Any new ideas on how to reduce nitrates, but more importantly, how to keep them down in the long term? My other tanks are all fine, just cannot figure out this one.
Should I just pull everything out, add a plenum to help out, add all new water, and just attempt to reacclimate everything?

 

[beth]

Describe your tank setup. Substrate, live rock, wet/dry?? ETC?
Obviously avoid getting fish that are prone to HLLE. I have yet to see a tang not have HLLE that was in a high-nitrate tank.

 

[beaslbob]

Originally posted by MorayM
...
Any new ideas on how to reduce nitrates, but more importantly, how to keep them down in the long term? My other tanks are all fine, just cannot figure out this one.

Add plant life.

 

[bdhough]

Also add feeding habits and the type of water you use.
You said you've kept other tanks fine, what kind?

 

[moraym]

70 lbs premium fiji LR, substrate is 30 lbs Aragalive live sand, 15 lbs crushed coral.
Feed them multiple diff types of flakes, two or three times daily, but the food never sits on the bottom, it's all eaten very quickly, especially by the engineer goby and the army of crabs.
No wet-dry, no room in this tank's current position. Two Millenium 3000 hang-on filters, with Purigen bag if I can keep it recharged enough.
Other tanks I have are all similar set-ups except they have space for wet-drys, so I run those. And my newer tanks have a plenum with Powerheads.

 

[moraym]

What plant life should I add to the tank?
I added Shaving Brush plants for a while, but they would always die fairly quickly, most likely due to a combination of crabs and snails that constantly picked at them, or the nitrates themselves. I know Shaving Brush plants are supposed to reduce nitrates, but I can't seem to keep plants alive long enough and as they die they just add to the problem.
Also:
All other levels in the tank are fine, so it's doing a good job of breaking down everything else into nitrates, and there is a lot of good growth and good organisms in the tank. Lots of copopods and other positive life, I've even managed to keep my Mandarin Goby alive for a year and a half, and he's still fat.

 

[moraym]

As far as water goes, I'm a graduate student with about six tanks now (four marine, two brackish) and my friendly pitbull mix, so my pet budget affords me only the water that comes courtesy of the city. Which I know isn't the best option.

 

[thomas712]

Originally posted by MorayM
so my pet budget affords me only the water that comes courtesy of the city. Which I know isn't the best option.
This is most likely where your nitrates are coming from, the city water. It seems obvious that your water changes are not going to reduce your nitrates.
I would suggest the following.
First test your city water for nitrates.
Reduce your feeding to once a day.
You seem to be spending good money on salt in the water changes and on food. Plus the purigen and purchase of a fish. If you reduce the water changes and reduce the food perhaps you can purchase some RO water with which to do a water change with the said RO. I would suggest a 30% change using the RO water. Just rechannel those funds toward the water instead of looking for other cures to the problem.
20 gallons of RO water cost me only $5.80. I think you can swing that a few times over can't you? so for $11.60 you can get 40 gallons @ .29 cents a gallon depending on your area and cost of RO vending machiens, and change that whole thing.
You could like Bob said add some macro algea's to your tank, but with that high of nitrates I think perhpas they might overgrow your tank, and unless you have a buddy that can give you some of these macro algea's they might cost more than the water which I explained above, and take longer to reduce your nitrates. Bob uses city water to and adds nitrates to his tank with every water top off, and quite frankly his tank is not the standard to which I have set my goals. I've seen the pics.
I truely believe if you adjust your spending and get some RO water then you will be pleased with the results.
You can always go and buy a sprig of culerpa if you wish and add that to the tank and see what happens.
Thomas

 

[moraym]

That's what I thought at first as well, but my other tanks don't have a nitrate problem and they are getting the exact same water.

 

[nm reef]

Very interesting situation...numerous displays but only one of them showing signs of nitrate problems. Another testiment to the old "each system is different" theory.
A few things mentioned about your problem system immediately caught my attention:
Using tap water...definitely may be a source of nitrates and may need to be addressed. Most places have sources of RO or even RO/DI water and either can help reduce nitrates. As for why the other systems have not been affected by the use of tap water...I can't help there. Possibly it'll simply be a matter of time.
It is very possible that the livestock in the problem system may contribute to your elevated nitrates...especially the 2 sand sifting stars. A well established DSB can and will help control nitrates. But your stars may be defeating the purpose of the sand bed. Even your goby may be a source of the problem. All of them will deplete micro infauna within the sand bed which in turn reduces the sand beds ability to function properly. Its my opinion that in order for a sand bed to function properly it needs to be undisturbed as much as possible. Also...your current sand bed may not be deep enough to be effective.
You feeding of flake foods 2-3 times a day definitely may be a source of nitrates and I'd suggest reducing your feeding schedule drastically for an extended period to see if that alone will help control nitrates.
Bottom line is there are known factors that contribute to elevated nitrates...and each should be addressed. Plus each marine system is different and each should be approached individually. Problems with one may never be seen in another.

 

[thomas712]

Ah of course the stars, (smacks self in head) I should have seen that one coming. Good call NM, those stars could very well be reducing the function of the sand bed, which would be just another factor to take into account.
Thomas

 

[broomer5]

I would say that having 30 lbs of live sand AND 15 lbs of crushed coral AND having the substrate disturbed by stars and this 9" goby .... has increased the likelyhood that your substrate is doing little if anything for denitrification.
Nitrates don't just appear - they are the result of nitrogen wastes, ammonia, nitrite.
Nitrogen wastes from fish.
Nitrogen wastes from proteins in uneaten foods.
Nitrogen wastes from processed proteins - again .. fish wastes.
Doing ten 20% daily water changes in a row - and not seeing "some" drop in nitrates - would lead me to think that your tapwater or saltmix contains some nitrate. Some being a relative term.
Running the purigen - I don't know. I don't use it.
It sounds like it strips the water of nitrogen wastes.
I think I would prefer the bacteria in the live rock and sandbed to so this job - both aerobic and anaerobically.
I ran a Millenium 3000 for awhile. Are the grids dirty ?
Personally I would consider using these filters for water circulation only and getting rid of the grid elements. And if you're using the carbon pads - make sure you replace them often.
The biggest factor I see though is the 2-3 times a day feedings.
I feed my tank 2-3 times a week.
Excessive food + little natural denitrification + possible nitrate from tapwater + dirty Millenium 3000 grids + purigen + crushed coral / sand substrate + wastes from fish = nitrate problem.
Macro algae grown in a refugium would help if you harvested the algae on a regular basis. Macro algae just growing in the display tank would be a disaster waiting to happen in that nitrate rich soup. Especially if coupled with high phoshates.
That's what I think at least.

 

[bdhough]

Can't argue with the sharks here.....
I will add on that unless your tanks are set up exactly the same way all around then you could wonder why one tank and not the other but there are to many factors that make every tank unique and therefore almost impossible to compare...

 

[beaslbob]

Originally posted by MorayM
What plant life should I add to the tank?
I added Shaving Brush plants for a while, but they would always die fairly quickly, most likely due to a combination of crabs and snails that constantly picked at them, or the nitrates themselves. I know Shaving Brush plants are supposed to reduce nitrates, but I can't seem to keep plants alive long enough and as they die they just add to the problem.
Also:
All other levels in the tank are fine, so it's doing a good job of breaking down everything else into nitrates, and there is a lot of good growth and good organisms in the tank. Lots of copopods and other positive life, I've even managed to keep my Mandarin Goby alive for a year and a half, and he's still fat.
regardless of where your nitrates came from, plant life will reduce them. I also recently thought I had a problem with nitrates and it turned out the test kit was too sensitive. So you might check your test kit. In my experience most of the nitrAtes come from livestock and with a good growth of plant life the quality of the input water irrelevant.
I also had a very similiar problem keeping plants alive due to my livestock and especially two anemone crabs. Your nitrAtes will not kill the plants but feed them. I now have caulpera and a red macro in my display along with brillo pad and gracilaria in my refug. I also have turtle grass in my 20g long macro culture tank. What I did was to culture the plants in an old 20g long and then each week transfer some of that to my display. Over a two month period, more and more of the plants survived in the the display. My 20g culture tank went from 160+ PPM nitrAtes to 0.0 nitrAtes in three weeks. My 55g display with refug is now 20 ppm.
To me you are over feeding but I feel you first priority should be establishing a vigorous plant growth. And I have heard similiar experiences with shaving brushes. And congrates on the madrian. You did much better than I did.

 

[zanemoseley]

Ya, I'd see if you can swing getting about a 30 gallon fuge with macros and a DSB, buy some RO/DI water, and do you not have a protein skimmer on the tank?

 

[moraym]

well it's not my source water, just tested a fresh batch of water and no nitrates.
Looked like I'm screwed until I can find a new place for my tank with enough room for a refugium.

 

[bdhough]

Your problem should be solvable without spending alot of money on a refugium. Try out some of the methods the sharks described if you haven't already