TetraTest Nitrate

[uncwalley]

Does anyone have experience with these? I've been using one for about 6 months now for a freshwater tank, brackish tank, and now a SW tank. The readings on the first two are always fairly normal. However, the new SW tank is bordering on ridiculous. It has been at my place for about a month. I took it and half its water from its previous home. It is 72g, has about 80lbs live rock (that's a guess), and the substrate is crushed coral. I am running a TetraTec 500 HOB, a HOT Magnum 350 cannister, and an oh-so-crappy Big Mombasa protein skimmer (that actually made a small amount of skimmate for a couple weeks). My nitrate readings are always on the high end of the scale. The difference on the color chart between 50 and 100 is stupid small, so I can't really pinpoint exactly where I'm at, but much higher than I want to be. Here's the real kicker. I've done water changes of at least 15 gallons every week since I got it, and the nitrate has never gone down. All that is in the tank is a small 3-striped damsel, a spotted watchman goby, a cleaner shrimp, and about 10 snails. I've gone to every-other day feedings and still no change, even after a 33% change yesterday.

A little more information that I know will bring the usual responses. I use tap water, that comes with a whopping 12.5 nitrate from the get-go. I realize this is not ideal, but I can't change that now. I realize that crushed coral is no good too and I am in the process of attempting to find sand at a decent price. Filters, I just rinsed and changed the carbon. Do I dare take the media out, especially the TetraTec bio-sponge thing?

Thanks.

 

[Atari]

Have you vacuumed the cc lately? If there's been detritus/food building up in there then that alone could account for the high levels.

 

[uncwalley]

I vacuum it every time I change the water, including yesterday. Of course, there is a lot of cc underneath the rock that I can get to. Who knows what is under there.

 

[Atari]

I think it's probably a combination of the tap water, substrate and filter media. Changing the substrate and keeping the media/sponge clean will help some but unfortunately until you change to RO/DI water you will simply be back to square one everytime you do a water change.

I believe there are nitrate removal systems out there but I've never used one.

First thing I would do is get a second opinion with another test kit, preferably a Salifert one.