Nitrates too high!! HELP!

[soonerzoo]

I've been testing my nitrates and they have been at about 20 ppm. I've done water changes and use purchased ocean water. I have a true percula, a coral banded shrimp, and 2 anemones ( conys), and some mushroom corals, and about 15 lbs of live rock. It's about 16 gallon aquarium. I'm running a small external hang on the back filter with activated carbon and some filter floss. What could be causing the nitrates? Should I not use an external filter and just use the live rock?

 

[Bifferwine]

Have you tested the new water you are buying? Test it before you use it. It may seem far fetched, but sometimes water is sold with high nitrates.

Other possible causes are overfeeding -- what kind of food do you feed, how often and how much?

Substrate -- do you have sand or crushed coral? And how deep is the bed?

You are not overstocked, although I worry about the anemones -- nitrates really should be at zero to keep those guys healthy (but I know, that's why you're here!)

How often do you change out and clean the carbon and filter floss in your HOB? That could cause high nitrates if it wasn't been cleaned often enough, but if kept clean, it won't contribute to high nitrates.

Also, how often and what size water changes do you do?

 

[soonerzoo]

Every couple of weeks I do about 20% water change. Substrate is live sand and couple inches thick. Yeah my anemones aren't doing so well. Probably the nitrates like you said. I haven't changed or cleaned the carbon or floss ever. Can I just take it all out and not have anything in the HOB?

 

[Bifferwine]

At this point, I think removing the HOB filter would be your best bet. If you are going to keep it running, it should be cleaned weekly. Some people think that's too much work -- I would agree. For a tank that size, doing a 10% or 20% weekly water change is normally good enough to keep water parameters in check. You need to be physically removing nutrients from the tank. When you use an HOB filter, particles and crap get trapped by it, and you remove those nutrients when you clean it. If you just leave it, they continue to rot in the tank and end up right back in the water.

 

[soonerzoo]

Will removing the HOB make the tank re-cycle because I would be removing the bacteria needed to remove ammonia and nitrite?

 

[Bifferwine]

No, you should have sufficient bacteria in your rock and sand.

 

[soonerzoo]

Ok thanks