I Don't Understand My Nitrates

[reb]

I have a 75 gallon reef tank that has been set up for almost 4 years. Maybe 10 corals, cleanup crew, clam, and 6 fish with a 5" regal tang being the biggest. I have probably 150 lbs of live rock and a 2" deep sand bed. I do regular water changes with tap water and ro water and haven't seen any difference in nitrates. I feed quality food once a day and make sure I don't overfeed. I run PC lights, skimmer, powerheads, and a tidepool 2 wet/dry system with the bio wheel. I run a charcoal filter in it with a amonia reducing pad also.
Salinity, ph, nitrites are perfect. Very little amonia, BUT MY NITRATES ARE AT 80ppm. I have never been able to lower them below 40ppm. I have also tried nitrate sponges, no help. I had heard that taking the bio wheel out might help, is that true? Any other suggestions would be very helpful. Thanks.

 

[mrmaroon]

I would give up a fish or two. And stop using tap water.

 

[ninjamini]

I have an eclipse system that uses a biowheel. 60-80 ppm every week. I did 2 things. remove the biowheel and add cleaner clams (littlenecks to be exact). Now things are fine.
You dont need the biowheel cuz you have live rock. Pull it out for 2-3 weeks you can always put it back later.

 

[mpls man]

I would start using r/o water for your water changes and slow down on the feeding.... i feed my fish every 3-4 days and corals every other day, your fish can go a couple days without food, your nitrates are more then likely coming from tap water and feeding every day adds to it. i would also remove the bio wheel as ninjamini said, your live rock is your filter system for the tank, also when your doing your water change go through the sand and clean that as well, do you have bio balls in you sump? sometimes they can be nitrate traps, some people say they can and some dont, since i took mine out i have no problems at all.

 

[jamnman]

I don't think a 2" deep sand bed is doing any good as far as nitrate removal.
Probably just making maters worse.
I suggest adding more sand and go to at least 4" deep or removing the sand.
Good Luck!
Make sure your source water test for zero nitrates also.

 

[nm reef]

A couple of things caught my attention...using tap water can contribute to water quality issues...the bio-wheel can be a source of nitrates especially after its been in place for a long time...the 2" sand bed may also contribute to your problems...its possible that there is excess food from the daily feedings...your bio-load may be more than your filtration can handle...also....
You mentioned test results indicating a trace of ammonia. What type of test kit do you use and how current is it. I've seen some of the "master test kits" give false readings especially with ammonia. It is possible that your tests are inaccurate. I'd suggest replacing them with Salifert kits and checking the results or maybe take a water sample to a trusted LFS and compare their results to yours. If you have a "master test kit" that is expired your test results may not be accurate.

 

[ophiura]

Number one above - get the readings checked somewhere using a different kit. Especially when it comes to nitrate, which can be really time dependent.
While you are at it, test your tap water for nitrates.

 

[reb]

Thanks for the great advise. I will take the bio wheel out, cut out a few feedings, and start working on the rest. My test kit is a "Masters test kit" I will order a Salifert very soon. Thanks all.