High Nitrates

[tgr26]

I've done freshwater tanks for a while and had a reef tank for about two years five years ago. I just recently started up again and I'm running into a problem.

I have a 30 gallon tank that started out with ten pounds of live rock. I let that set for about a month, the nitrates spiked and then fell to zero. After about a month of that, I added fifteen more pounds of live rock. This was two months ago. My nitrates spiked to 40 ppm, and they've been down to 10ppm for the past few weeks, but haven't gone down to 0.

Shouldn't the cycle almost be complete?

I do water changes about twice a week. I've tested the water I'm putting in the tank, and the nitrates are at 0. I'm using a water conditioner and pH buffer because our water is too acidic here. I have 130 watts of compact flourescents and some polyps, starfish, and other critters are in my tank from the live rock. I had some really good growth of coraline algae, but just this past week it's starting to fade from pink to white.

Is it possible that what I'm adding to the water is causing nitrates to stay high?

I'm also thinking it might be my skimmer. I am using this little guy:

http://www.drsfostersmith.com/produc...m?pcatid=21416

Any help is greatly appreciated!

[sporto0]

Well 10 ppm nitrates is not a high number, if you have anything live in your tank, you are going to have nitrates, most nitrate removal is done through water changes, very little is converted to nitrogen gas by bacteria. Remember the Nitrogen cycle consists of Ammonia to Nitrites to Nitrates & then Nitrogen Gas in small amounts. A better skimmer will help, a refugium with Macro Algae will use up nutrients as well. I would not continue to use tap water though if you plan on coral keeping, invest in a 4 stage RO/DI filter, you will be glad you did. Welcome back & good luck.

[Zappo]

Nitrates are the end result of cycling your tank. Bacteria deep in the rocks will slowly reduce it, but for the most part nitrates have to be removed by doing water changes. Growing macroalgae in a refugium also helps.

Also, you should generally cut the rated tank size in half when buying skimmers. It depends on your bioload, but when they say up to 30 gallons I think they're referring to an empty tank...

[VoiceInTheDeser]

10 isn't all that high and with that much live rock in your system, the odds of having something alive in there (in addition to the algae on the rocks) is fairly good I would think. Anything alive will create nitrates.

To answer your question though, I can't think anything you're adding to the water is the cause.

[hollister]

Water changes twice a week . how much you changing?

Also adding so much rock at one time is a large load at one time. You have an unseen bacteria in the water and they need time to multiply. Adding so much rock could cause a die off.

If you have no fish a skimmer isnt needed.

Whats used for water flow in there?

[sporto0]

Originally Posted by hollister

Water changes twice a week . how much you changing?

Also adding so much rock at one time is a large load at one time. You have an unseen bacteria in the water and they need time to multiply. Adding so much rock could cause a die off.

If you have no fish a skimmer isnt needed.

Whats used for water flow in there?

What?
You don't need to do water changes twice a week.
Adding rock can NOT cause a die off.
If your doing a reef tank a skimmer is almost a must.
What does flow have to do wtih nitrates???

[hollister]

I asked how much water you are changing each time.

If the rock wasnt fully cured it could cause die off. But the bio load alone on a newly cycled tank could also die off if its forced to higher needs. If your cycled you want to make changes in small increments to put less stress on your tank. Water is also a living bio cummunity.

Water flow is very important , your salt water tank with good flow will create a gas echange at the surface reduceing un wanted readings.Your tank breaths at the surface.
Also good flow reduces waste and other material to collect and cause un wanted readings.

You have a 30 gallon newly cycled tank and you add 15 lbs of rock, then your asking the bacteria to handle this load and it cant so some will die off.

Skimmers remove waste that fish create and a little waste is good for pods and bacteria and also corals. So if you remove to much waste your removeing a food source. The skimmer reduces ammonia whene stock is higher.

[tgr26]

I change about 15% each time. For water flow, I have a power filter and a power head going.

[hollister]

You can do a water change during the cycle but its not needed. 3 weeks should be enough. You havnt added any other stock or lights or anything?

[tgr26]

No, I haven't.

[hollister]

Could be the water changes.

[sporto0]

Originally Posted by hollister

I asked how much water you are changing each time.

If the rock wasnt fully cured it could cause die off. But the bio load alone on a newly cycled tank could also die off if its forced to higher needs. If your cycled you want to make changes in small increments to put less stress on your tank. Water is also a living bio cummunity.

Water flow is very important , your salt water tank with good flow will create a gas echange at the surface reduceing un wanted readings.Your tank breaths at the surface.
Also good flow reduces waste and other material to collect and cause un wanted readings.

You have a 30 gallon newly cycled tank and you add 15 lbs of rock, then your asking the bacteria to handle this load and it cant so some will die off.

Skimmers remove waste that fish create and a little waste is good for pods and bacteria and also corals. So if you remove to much waste your removeing a food source. The skimmer reduces ammonia whene stock is higher.

You are absolutely wrong about the live rock, if it is not fully cured it will cause a spike in ammonia which is from die off of the uncured rock, it will not kill your existing bacteria colony & it does not cause more die off. The bacteria must grow to handle the load put upon it & uncured rock will produce ammonia, but that's not what you said in your first post at all, you said adding rock will cause die off? Water flow is important & gas exchange at the surface is also important, but has nothing to do with nitrates, they are only produced by the load put upon the system. If you had a tank with zero flow & zero livestock, your nitrates would read zero. A good skimmer will help reduce nitrates, which is what the op was asking & of course water changes are the best way to reduce any high nutrients, including nitrates, but 10 ppm nitrate levels would never require twice a week water changes. You are not very clear thus I question your statements.

[sporto0]

Originally Posted by hollister

Could be the water changes.

What could be the water changes? A nitrate level of 10 ppm is totally normal & acceptable.