Nitrates just won't drop...what to do?

[runway1]

I have a tank that's 7 weeks old tomorrow (2/25). nitrates have been at 40ppm for 3-4 weeks now with no movement. Ammonia and nitites have been 0 for over a month.

I would like to add a coral or two. What's up with my NO3's not coming down? Thanks all!

REF INFO:
55 gal
65# LR
CC base
UV & PS running
Cleaning crew
No fish

[Phyl]

Do a major water change and see what happens. What type of filter are you running? What kind of water are you using (RO/DI or Tap)? Has your UV been running during the cycle? What kind of salt are you using? If nothing in your setup is contributing to the NO3 problem then the WC should fix your problem. It is common to do a massive water change at the end of your cycle to bring the NO3 in line.

[mattmku]

unless you have set up your tank for denitrification (deep sand bed, refuge, etc...) your nitrates will not just drop. Nitrates are a product of the nitrogen cycle and are not consumed by anything in your tank. Like Phyl said, a water change is one option to bring down your nitrates. Another way to reduce these is addition of a refuge with a DSB or special types of denitrifying plants.

[runway1]

What kind of sand for a DSB and can I mix it with my CC? Also, I've seen plenty of reef tanks without a fuge, what are they doing? Is the DSB the only other option?

[runway1]

Oh sorry Phyl; I use purchased SW from the lfs and my UV was turned on in week 3. It runs 12 hrs/day. Also what do you mean by "wild caught" should solve my problem?

[lando]

What kind of sand for a DSB and can I mix it with my CC?

Aragonite Sand, not silicate sand. YOu can mix them but the sand will just settle to the bottom and you will be stuck with the same problem of the CC catching detritus. Best to get rid of it all together. What is currently in the tank and what is your feeding schedule?

[RMPD109]

As lando said removal of the CC substarte will be a good step to lowering nitrates. Nitrates tend to collect detritus and ultimately raising your nitrate levels. Either get in a routine of vacuuming the CC regularly or remove it. The cycle will be the biggest cause of nitrates in a new tank such as yours. Did you perform a large water change at the end of the cycle?

[runway1]

Yes, I did a~25% water change after my NO2's went to 0. I've done weekly changes of 10%-15% ever since. my feedings are early evening, once a day.

My CC is very fine, like sand. Seems like it would mix well sand without separating.

NOTE: I started my tank with 25# LS and 50# CC. Was that a good choice? At least I thought so, at the time.

[Phyl]

Sorry, Water Change, not wild caught. . Try a larger water change (30-50% or 2x 30% a couple of days apart). You're right. Plenty of people manage without DSB or Fuge (I'm one of them, I have a 120, no fuge and a shallow sand bed). If it is fine like sand then I can't see a reason it would behave differently than sand (anyone have a thought on this?).

You could try turning off that UV until after your water stabilizes. You may also want to check the nitrates in your LFS bought water to make sure that you aren't introducing them with the water changes. What kind of filter are you using?

[runway1]

I use a wet/dry filter with balls removed so it's really not a "filter" as much as a sump. Before the wet/dry, I have two sediment filters. First, the sponge type at the overflow and then a sock at the wet/dry/sump.

The CC I used was extra fine O-O grade. When I mixed in the 25# LS bag, it wasn't much different.

[JPloman]

You can get a NO2 sponge, put it in one of those cloth bags and attach it to a power head in your main tank. That way you are sure that your water is getting filtered really well with the NO2 sponge. I would also put the balls back in the sump, it really helps the system.

[lando]

I use a wet/dry filter with balls removed

good choice, bioballs can tend to cuase nitrates to rise. You may wnat to consider filling the bioball chamber with LR rubble. It is a great filter media and will give you great biological filtration.

[JPloman]

Originally Posted by lando

good choice, bioballs can tend to cuase nitrates to rise. You may wnat to consider filling the bioball chamber with LR rubble. It is a great filter media and will give you great biological filtration.

REALLY!?!?!?! I thought they were supposed to help filter out the bad stuff.

[RMPD109]

Bio balls have great surface area for bacteria growth. The problem is that the crevices also trap detritus. As we all know detritus will lead to nitrates and then you have a problem.

[JPloman]

Well fancy that. Maybe we should pull them out of our tank and give them a bath every once in a while. Would that be a wise idea?

[RMPD109]

If you go that route take out a section with the next water change. Clean it then replace it. At the following water change do a different section.

It is best to remove the bioballs and replace with LR rubble. Just be sure to keep the rubble submerged. If you change over it would be best to do it at about 20% at a time to keep the biological filtration up.

Good luck either way

[lando]

Maybe we should pull them out of our tank and give them a bath every once in a while

that is a great idea. Just make sure you use SW to rinse them. When you do a water change just rinse teh bioballs in that. As mentioned, replacing the bioballs with LR is the best course of action.

[runway1]

Thanks for the input all. To answer the question, YES, I do have rubble in place of the balls. Not much though. About 2-3 pounds.

[electrikat]

It would help if you filled the bio ball spot with lr rubble.