Nitrate Problems Driving me Crazy. HELP!

[toccoa fish man]

Alright, here's the story. I got a mature reef tank from a friend several months back (125 gallons), with mostly hardy soft corals and a few invertebrates. I have been unable to bring down nitrates since then, in spite of several large water changes. My fish are just fine (clowns, tangs, chromis, gramma) and candy cane, GSPs, some big condis, some ricordeas, a cuke, a horsheoe, and sponges are just fine.

However, I've lost a leather coral, a ton of emerald crabs and porcelain crabs, shrimp, snails, zooanthids, and mushrooms. Mostly, I'm ticked off and ready to go postal, because I can't get the tank looking pretty, where soft corals stay alive and the colors pop. I have to assume this is due to the nitrates, which have stayed between 80-120 no matter what I try. This tank has been all labor and no return so far.

I tried to make a do-it-yourself refugium, where I placed Nitrasorb pellets underneath bio balls and packed the rest of the space with macroalgae. I've also got a bag of purigen sitting in the in-flow and in the overflow box. I quickly realized that nitrate binding chemicals aren't going to do the job. Here are the culprits I've thought of....

1) My sand bed is too shallow? I know it is, and it needs fixing. I'm guessing my problem is that it is belching out unbelievable levels of filth that the refugium can't touch, since it started out as an old tank. The stirring up of the tank move would also explain why it was not a problem at my friend's house, and it suddenly is a problem at mine.

Should I try to make a deep sand bed in sections (and replace the sand in there), or will I just stir up more filth doing this and kill everything? I made the mistake of over-vacuuming one water change, and this is when I lost all the mushrooms.

2) Add a 2nd protein skimmer? I'm suspicious that the one I have now is just not doing the job.

3) Wash off the liverock in a separate 'cleaning' tank and return it after it has been cleaned? Someone told me that the liverock could be the problem, since I probably have too shallow of a bed, and its full of aerobic bacteria making nitrates with nowhere for them to go.

Please offer me any insight you can. This is like one of those situations where I'm having to pick through bad advice to get to what seems logical. So far, the advice I took with the refugium and the water changes has been about as effective as shooting an elephant with a BB gun.

 

[enderg60]

First off, when nitrates are that high do not do large water changes. A fast drop in nitrates can be harmful since they are already used to the elevated levels.

Next we need to know the size of the fish and how many there are, and how much you are feeding. As well as how much live rock is in the system.

When i deal with old systems like this that were not well maintained I usually throw a sulphur denitrator on them. It will slowly drop the nitrates along with small water changes down to safe levels where you can either fix the problem or leave the reactor on.

 

[mvm]

I would start by vacuuming out the sand and replacing, gradually until you have replaced all sand. Taking the rocks out and cleaning them is not a bad idea, either. I wouldn't worry about a deep sand bed, but my guess is that most of the nitrates are trapped in the sand and rocks.

 

[ralph atl]

EnderG60;700959 wrote: First off, when nitrates are that high do not do large water changes. A fast drop in nitrates can be harmful since they are already used to the elevated levels.

Next we need to know the size of the fish and how many there are, and how much you are feeding. As well as how much live rock is in the system.

When i deal with old systems like this that were not well maintained I usually throw a sulphur denitrator on them. It will slowly drop the nitrates along with small water changes down to safe levels where you can either fix the problem or leave the reactor on.

MvM;700961 wrote: I would start by vacuuming out the sand and replacing, gradually until you have replaced all sand. Taking the rocks out and cleaning them is not a bad idea, either. I wouldn't worry about a deep sand bed, but my guess is that most of the nitrates are trapped in the sand and rocks.

yes above!

I would do weekly water changes of about 20-30%....

add a dual brs reactor with rox carbon (or purigen if you have tangs) and gfo. Change weekly.

nitrates:
either a denitifier or carbon dosing

done.

 

[toccoa fish man]

I suspected the sand and rocks were the major source of the problem. To answer previous questions...

1) The tank is not loaded up for a 125. The tang is about 4 inches, while all of the other 6 fish (clowns, chromis, gramma) are 2 inches or less.

2) We are not feeding an unreasonable amount. We give the fish and anemones what they will eat in a few minutes every other day, plus we clip a sheet of seaweed onto the tank for the tang.

Can you recommend a good sulphate denitrator reactor? I'm not a complete novice, but I am relatively new to the hobby (2 years), so I'm still learning my way.

Edit: Also, I would estimate that there is about 80-100 pounds of liverock in the tank. Most of them have significant patches of purple algae, but none of them are completely covered with anything. They could definitely look more alive, but I'm sure the nitrates have a lot to do with this. The only polyps that are really growing are the green stars and candy canes. Everything else seems stunted.

 

[ichthyoid]

Toccoa Fish Man;700976 wrote: I suspected the sand and rocks were the major source of the problem. To answer previous questions...

1) The tank is not loaded up for a 125. The tang is about 4 inches, while all of the other 6 fish (clowns, chromis, gramma) are 2 inches or less.

2) We are not feeding an unreasonable amount. We give the fish and anemones what they will eat in a few minutes every other day, plus we clip a sheet of seaweed onto the tank for the tang.

Can you recommend a good sulphate denitrator reactor? I'm not a complete novice, but I am relatively new to the hobby (2 years), so I'm still learning my way.

Edit: Also, I would estimate that there is about 80-100 pounds of liverock in the tank. Most of them have significant patches of purple algae, but none of them are completely covered with anything. They could definitely look more alive, but I'm sure the nitrates have a lot to do with this. The only polyps that are really growing are the green stars and candy canes. Everything else seems stunted.

I agree with the above, btw.

-what kind of skimmer do you have on this tank?

-if you are going to do any type of carbon dosing, you will need a very good skimmer.

FWIW- I prefer 'monster' skimmers, as too big does not matter. Too small does.

I agree with getting the gravel out. That is the source of the nitrate. Then start over with new gravel.

Doing water changes has a limited effect. Why? Because you are always taking out a fraction of what's there. This is proven.

-jmho

 

[irahmatulla]

Every one has great ideas, but aren't "bioballs" also know as a nitrate factory? Also, I am a big fan of the DSB, how much LR do you have in this tank?

 

[toccoa fish man]

Everything I've read about deep sand bottoms has been positive, so I will probably lean towards that. There are about 80-100 pounds of live rock right now.