Substrate confusion and HIGH nitrates

[smilingcrafter]

I have a 55 gal. with about 40 - 50 lbs. of LR and about 3 - 4 inches of Florida crushed coral aragonite (2.0-5.5 mm) for the substrate. I have a skimmer, a bio-filter, and a mag 350. I also have about 5 fish some mushrooms, leather, a bulb anemone and an assortment of crabs ans snails. I have had the tank for about 2 years. I am currently fighting nitrates, sometimes 80ppm. I have done water changes, half, 3/4,s, and today a 95%. I am still having problems. I am wondering could the nitrates be coming from the substrate? I am also confused about the DSB I have been reading about, is what I have considered sand? or is it to big? Is what I have bad for a substrate? What do you think about the nitrates?:confused:

[webbstock]

Nitrates are a result of a build up of decaying organic matter in the tank. Some very common sources are 1) over-feeding 2) excessive detritius trapped in filters 3) dead fish/inverts

In your case, I would suspect one of two main culprits. Check your mag 350, if you are running lots of filter material, it may be full of detritus and that's giving off the nitrates.
Secondly if lots of detritus is falling into the space between the sand grains, that could be a source.

To fix the filter, try changing out any filter material

For the sand, make sure you have some sand sifters turning over the sand (stars, nassarious snails etc) or vacuum it very well with each water change, stirring it up a bit. If you have a sump or refugium add macroalgae (cheato etc.) and that will utilize lots of the nitrate.

[Myka]

My best guess is the Nitrates are caused by your sandbed. Your sandbed is very coarse. It should be more like 0.5 - 2 mm or even 0.1 - 1 mm. Detritus gets stuck in the spaces between the larger sand grains, and has to break down. The key in saltwater aquariums is removing the organic matter BEFORE it breaks down into nitrates. This is why we have protein skimmers. That's what a good protein skimmer does. However, it can only get the stuff suspended in the water column.

If I were you I would change out your substrate into a finer grained sand. CaribSea makes excellent substrates, just pick a nice fine one. I use CaribSea Aragamaz Sugar Sand 0.2 - 1.7 mm. It's an "oolitic" sand which means it's round shaped, and moves real easy instedad of packing together. To change out your sandbed, change like 1/6th or 1/8th at a time. Just remove 1/6th scooping it out from one side with a little cup trying not to blow it arround too much (turn pumps off), replace it with the new sand (pre-rinnsed and still wet). Then in a week change out another 1/6th of the old stuff. Watch your Ammonia and Nitrite levels, if they go up then you changed too much sand in one go, and you'll need to do a smaller portion next time. It's ok if there's some of your old stuff mixed in since that's good for diversity, however you are trying to remove as much as possible.

As already stated, your power filters may be the cause as well. I personally run two small sponges in my power filter, and change one out once a month or once a week depending on bioload. I watch my test readings, and if the nitrate starts to go up just a bit I change one sponge out for a new sponge, and remember to replace it a bit earlier next time so I can catch it before the nitrate goes up.

[bertoni]

I agree that the power filters and the substrate both might be causes. I'd remove the power filters <b>slowly</b> and replace the substrate. Replacing the substrate is a lot of work, though.

Water changes are largely useless for nitrate problems, since the levels jump back up rapidly. I avoid changes over about 25% except in cases of emergency, to avoid possible shocks to the animals.

Growing and harvesting a macroalga might help a lot. This article covers nitrate problems in detail:

http://www.advancedaquarist.com/issues/august2003/chem.htm

[Myka]

Honestly, the only reason I run a powerfilter is to keep a sponge full of bacteria for my QT. :)

[smilingcrafter]

I know I probably sound like a dummy, but what kind of sponge are you talking about?

[Myka]

I have an AquaClear power filter. The filter media consists of a sponge, a bag of charcoal, and a bag of Ammonia remover. I just use the sponge. :)

[zoomfish1]

Unless you are cleaning it ever other day it is prob one of the nitrate sources. I don't think I would sacrifice the amount of nitrates you can get rid of without the sponge just to have some for a QT. If you put a rock in there you will have bacteria.