Nitrates
 

Hi,

I'm asking this question cause I'm stumped. I have a 20 gal. aquarium with only 7 lb. live rock (so far), 1 1/2" of live sand, and 1 false perc. clown fish. My temp is at 80, amm., nitrite are at 0, ph is at 8.2. but my nitrates are at 5.0. With only 1 tiny fish and just the live rock, what would cause the nitrates ? Should I be concerned ? How could I maybe bring it down ? I personally don't think it is anything to worry about, but if it could be better, I'd like to make it that way. I am not running a powerhead or a skimmer. I have a Eheim hang on back filter that is for a 40 gal. aquarium this is in the middle of the aquarium and really does cause a lot of water movement both underneath and and on the surface. Never have a film on top of water and it is crystal clear. I use distilled water for water changes and change 3 gal. of the water every other week now, was doing it once a week. I do still have diatom algea, but not too much. Nemo seems to be happy as can be. This aquarium has been up and running for about a year now, live rock was just added within the last month. Nemo has been living there for about 7 months. :-D

If you did not have Nitrates, that would be an interesting topic. What you have is predictable levels of Nitrate that will continue to gradually climb. That being said, lets talk about why...

Before we get into a long discussion, tell me more about the Eheim filter. What type of filter media do you use. Also, in addition to Nemo, what other livestock do you have? Any shrimp, crabs, snails, etc? What is your feeding routine and what types of foods? Finally, if you could post pictures it would be great.

To go along with the great questions Pasfur asked, I'd also would like to know what type of LR you have? Was it cured and if so by who? you or the person you got it from. IMHO it may be die off that could be causing the nitrates to come into the tank. Keep doing water changes, but you will have them continue to rise as time progresses. Also, how often do you change the media in the filter?

Why am I here? There is no need for me. Great great great point. This is much more likely the case than my misguided questions above. Lets hear about the live rock....

lol, you are a great asset to the hobby!

I am using the cartridges that are made for it, charcol, cardboard kinda things, rippled !
Other than Nemo my daughter popped in a small peppermint shrimp on me about 3 weeks ago
I feed once a day, either just the marine flakes (occasionally) ,or some frozen mysis shrimp or brine shrimp .
I will get the photo uploaded and posted asap.
P.S. the live rock was in a tank of saltwater with a couple powerheads going at the LFS when I bought it. They told me it was cured. I know they have had it for awhile.

Got my order from Macro Rocks today, it's beautiful !

This is actually a great testimonial to why we run our marine aquariums with live rock, live sand, and a protein skimmer. Your Eheim filter is designed to do 2 things:

The first is to catch particulate matter and remove it from the viewing area. This makes the water look clear, but it does not remove the particulates from the water flow, and as a result phosphates are introduced into the aquarium, causing your continued diatom bloom.

The second function this filter was designed for is chemical filtration, which is accomplished by the activated carbon absorbing organic waste. This is a nice feature, but the carbon is very inefficient at doing this, as compared to a protein skimmer, which directly REMOVES the organic wastes. Additionally, the carbon is only effective for a few short days, and most people are not willing to change the carbon pouch this frequently.

Unfortunately, it is what the Eheim filter does by accident that causes the Nitrate problem. The filter pads and activated carbon both become biologically active within a few short days. This leads to the nitrogen cycle effect that you learned in freshwater, with ammonia becoming nitrite, and nitrite becoming nitrate. The nitrate is then introduced into your aquarium, leading you to wonder how and why. You have been fortunate that your stocking level is very small, causing such a small buildup of nitrates to occur.

The next problem with your setup is the sand depth. With such a light stocking load, the sand bed could effectively provide for denitrification to remove the nitrates, converting them into nitrogen gas. However, your sand bed is not deep enough for this to occur. You really need between 4'' and 6'' depth for high effeciency in denitrification. Additionally, your sand bed is greater than 1'' in depth, which tends to result in detritus accumulation on systems that do not have denitrification occuring.

Bottom line, I would suggest adding more live rock and adding a protein skimmer. You could then remove this Eheim filter from the system. Additionally, you need to make a decision on your sand bed depth. You can remove some sand so that the depth is less than 1'' and detritus accumulation likely will not occur. Or you can add sand to increase the depth to 4'' for denitrification to occur.

Thanks much. We are in the process of adding more rock and I was planning on adding more sand this weekend, I did the search on adding sand to an already in use tank. It's great to know I can eliminate the filter, that makes me really happy. I change the media in the filter every two weeks. O.K. in a nutshell. . . .get approx. how many lbs. live rock ?, add to the sand so that is approx 4" deep, then do I wait for all my readings to go back to normal after adding the rock and sand, then take the filter off and throw it away ??!!

How many pounds did you order from Marco rocks? If you did 25 pounds, and you already have 7 pounds of live rock, then you should be good to go.

I would not throw the filter away. Instead, I would move it to a 10 gallon aquarium for a quarantine tank.

Thanks so much, what you explain makes really good sence now. I only ordered 10 lbs. of rock but am going to the LFS to get more tomorrow and I will add more sand to the sandbed. Thanks again. Now I'm off to ask a question about sump media !! Never a dull moment when you are getting started.