How to lower Nitrates?

[reefermadness]

larger skimmer, more water changes, carbon dosing (I recommend biopellets).

[shootingstar]

larger and/or better quality skimmer, weekly instead of bi-weekly water changes, feeding less and only every second day and if you can live with the "bare-bottom" look remove the substrate

[BigDev]

+1 for better/bigger skimmer and bio pellets. I was having the same problem, so I increased water changes and reduced feeding, after a month no real change. So I tried Nitrate destroyer from tailored aquatics. It helped, but after a month of this my levels went from 40 to 30. I have a 90 w/40gal sump. Running a vertex in-180. So I tried biopellets (vertex) I put in the minimum suggested. After 3days I had a bacteria bloom that lasted almost a week. Then the skimmer started to really pull out some nasty stuff. When the tank cleared my levels had dropped to 0.25 and as been there consistently for the over a month... I am also water changing 20% every 2 weeks

[cwatkins]

Bio-pellets for sure. A good way to go ULNS. Just be careful as running a lean system like this, things can go wrong quicker (from what I've heard). So just keep on top of your params.

[fishytime]

How big are the tanks?..... how many and what kind of fish are in the tanks?

[Bblinks]

+1 on pellets, but before you start adding anything take a sample of your water and get your lfs to test it for you. I would definitely make sure your test kits aren't expired. Also one thing I noticed, quality test kits are key to success. If the results are the same then let us know how your tank is stocked and your feeding regime in details so we can try to figure out what the problem lies.

[Money pit]

When I had a 30g skimmer less lps/softy tank, I used to do 50% water changes a week. There was always some NO3 from feeding the lps, but usually only around 5ppm at water change time. It was vital to match temp and ph, if this was done there wasn't any problem caused by the large water change. May not be a long term solution, but it will cut down the NO3 fast, while you look for the cause.

[Midway]

So more skimming the better to get nitrates down? What about two skimmers?

[Midway]

Test kita are fine i think, i just bought them like a month ago.

[Bblinks]

What brand of test kits do you use? Honestly take a sample and give it to your local fish store, they will be more than happy to help you and test it for you. I used to run 2 skimmers on my 72 gallon, it worked just fine. It seems when it comes to skimmers more is always better.