Nitrate levels up and staying up......

[goose]

I have a 55 gal. tank that has been up and running since July of 2002. I have a 2 to 3 inch DSB of argonite sand, and 55 lbs of live rock. The tank has been cycled since Sept. 2002. I also have 3 blue damsels, 2 yellow tail damsels, around 10 snails, 15 bluelegged and red legged crabs, four emerald crabs, 1 porcelain crab, 2 brittle stars and a large chunk of calerapa growing in the tank.
My problem is that several months ago, my nitrate levels when way, way up. I have not lost any fish or inverts from the nitrate levels going up. I also was up to date on my water changes. When the nitrates started going up, I was doing a water change of 50% once a week. At the advice of the lfs, I threw the chunk of Calerapa in to try and eliminate the nitrates. The plants are growing, so I'm assuming some of the nitrates are being removed. However, I cannot get the nitrate levels to go back down. I would like to add some more fish, but feel that I can't without getting the nitrates down first. Any other suggestions of getting my nitrates down?? I thought maybe some feather dusters to help with lowering the nitrates, but I'm afraid the crabs will pick at them. Without starting over, I don't know what else to do. PLEASE HELP!!!

 

[ocellaris_keeper]

Ok - relax, your fish can handle high nitrate levels, however if you have corals your in for trouble.
You really shouldn't do more than a 20-25% water change a week (changes the biofiltration and can cause a re-cycle of the tank. A 50% water change is somthing you do when ICK breaks out or a fish dies and your ammonia spikes.
A plenum DSB could solve your problem but with an established tank rebuilding the entire ecosystem is not a good idea. There is a sponge that you can add to a cheap filter (one of those hang on ones from Wal-Mart) that is designed to remove nitrates, but I have no confidence in it.
You could add another 1.5" of SWF Live Sand and that would certainly help in the long run.
Another good option would be a refugium hang on filter. This is a filter designed to be a small ecosystem with live sand and nitrifying bacteria that just love nitrates.
It's kinda of adding 50 lbs of calerpa into your tank.

 

[broomer5]

In my opinion - in a 55 gallon tank with 5 damsels - you should be able to control nitrates.
Here's a couple things to consider.
As you know - nitrates are the result of nitrite/ammonia.
If your ammonia and nitrite levels are zero - then your biological filtration is functioning properly. Nitrates will be the end product.
If you're overfeeding this tank - high levels of nitrates may result as well.
Are you using RO, RO/DI or tapwater ?
If using tapwater - this could be part of the problem too.
2-3 inches of sand - many would agree that you should increase the depth to 4-6 inches for best results.
Even with a 6 inch deep living sand bed - it can take months for it to actually begin to reduce nitrates.
In my experience - the combination of light feedings, doing partial water changes with nitrate free water, doing evaporated water top offs witih nitrate free water, utilizing a LIVE DSB and installing a refugium/harvesting macro algae .... all contributed to my tank finally reaching non-detectable nitrates. This took over 6 months to happen.
Lastly - what nitrate test kit are you using ?
What is the reading ?
Have you had this value verified with another test kit ?

 

[dreeves]

Back off your feeding, reduce the water changes to about 15-20% weekly, and let the calurpa do its thing...Nitrates are a portion of the weeds diet...as it grows...it will consume more. To maintain the NO3 to 0, it will take time to catch up.