So my cycle seems to have stalled at high nitrates. Help please? :D

[Xyres]

It has been about 3-4 months since I have started my tank. It is a 55g with canister filter which I will be upgrading within a year. I have two cleaner shrimp, two clownfish, and emerald crab and some hermit crabs as well as 50-60 pounds of live rock in my tank at the moment.

Now that we have some background on my tank here is my issue. My Nitrates will NOT go down no matter what I do. I clean my filter, run a protien skimmer, do water changes and monitor food intake, have excellent water flow as well as use RO/DI water. What would be the reason for my nitrates still being around 25-40? It is really annoying as I have been doing everything I can to keep it down.

Here is what my water was at today:
Nitrates: 30
Ammonia: 0.1
Nitrite: 0.1
PH: 8.2

Any help would be great and I will answer as many questions as I can to help figure this out.

[mseepman]

Not totally sure why your nitrates stay high, but I would start by verifying that your test kit is giving you good readings. Could you verify what you run inside the canister?

From there, you could look at chemical/filter based methods of reducing them. Several companies offer liquid nitrate reducing products. Biopellets are also very popular and can run from an external fluidized reactor for a pretty reasonable price.

[Aquattro]

Sell the canister filter and use it for corals or something. There's no good reason to run a canister, and it can and usually will lead to higher nitrates.
50 pounds of rock and a good skimmer are more than enough for your bioload.

[FragIt Dan]

The fact that you have any ammonia and nitrite is a bit of a concern. Essentially, your nitrates are the last stage in your nutrient cycle (not to be confused with your tank cycling). You need to look at what nutrients are going into, or are already in your tank. Perhaps over feeding? Perhaps insufficient water changes? How big and how often are you doing water changes into what size of a tank?
Dan

[Enigma]

How does your salt water test after mixing? What ppm disloved solids is in your ro/di water?

[gregzz4]

What brand of test kits are you using ?
What is inside your canister filter ?
How do you clean your canister ?
How often and how much water do you change ?
Did you cure your LR ? Where did it come from - a running system could give you lots PO4 and NO3 leaching that will take time to dissipate ....

[Xyres]

Alright I will try to answer all these questions.

-I don't think overfeeding is an issue as I only give them what they eat a couple times a day.
-I am doing water changes everywhere from 1 week to 2 weeks and sometimes more often as I am trying to get the nitrates down.
-My salt tests at 1.024 using a refractometer.
-Not sure about dissolved solids in my water as I get it from a business who's line of work is purified water who's rep is well maintained with fish keepers.
-Inside my filter is bio foam, foam, biomax and carbon.
-For water changes I do between 20-40%. I have increased recently as I am trying to force water levels to go down.
-My live rock came from a supplier that my work deals with based in Vancouver. It was per-cultured.
-I use nutrafin for my test kits.

Any help and criticism are appreciated as I need all the help I can get.

[Enigma]

You need to test your new saltwater for everything before doing a waterchange: but especially ammonia, nitrites, and nitrates. You need to be sure that you've got zeros for all three in your mixed water.

If all three are zero, that eliminates one possible source.

If all three are zero . . . Something is decaying in your system: beyond what your bio filter can handle. It could be gunk in your filter, over feeding, dying critters . . . ?

[Spyd]

I would remove the canister from the system and use a reactor to run GFO and/or carbon. The foam in the canister acts as a nitrate factory as it collects food and dietritus. Also, are the hoses going to and from the canister ribbed? If so, gunk and debris settle in these ribs and decay as well.

I agree, that live rock and skimmer should be sufficient for your bioload.

[Cal_stir]

Remove the foam from the canister filter and keep the biomax and carbon.
The bacteria that eats nitrates is anerobic and only lives in very low oxygen enviroments like a denitrator or deep sand bed, my personal experience says that DSBs are useless and more problematic than they are worth(I'm sure some will argue), the other method is to grow aerobic bacteria(lives in oxygen) with a carbon source ie, biopellets, vodka, sugar or vinegar dosing, by growing the bacteria nitrate and phosphate are used are used up building the cell walls of the bacteria, the bacteria dies and gets removed by a skimmer thus removing the nitrate and phosphate from the system.
You must have a good skimmer for this method. Growing macro algae will work to, but that requires a lighted refugium and is somewhat limited to amount of nitrates it can take up.
I think the simplest most effective method you could employ is vinegar dosing, read this.

http://reefkeeping.com/issues/2008-08/nftt/index.php

IMO sulphur denitrators rule.