Can't get the nitrates down

Kevomac

Kevomac

New member
I have had my 120 FO for over ten years now, and I have always battled high nitrates. The tank is an Oceanic with dual overflows draining into a DIY sump that I bought a couple of years ago when the original trickle filter sprung a leak. I originally moved all of the bioballs into the new sump, but recently removed most of them and converted a small section into a fuge, by putting chaeto into it, adding a light (5500K compact fluorescent from HD) and adding a piece of egg crate to keep the chaeto from washing over the bubble trap. I currently have all of the water draining into the fuge, and the chaeto has sunk to the bottom, where it is still alive but not growing. The tank has a small amount of live rock (maybe 50 pounds). It currently houses a coral beauty angel (had him ten years...he's survived everything), a 4" niger (had him for years, started out about 1"), a tomato clown and a small snowflake moray (had him for years too). When I tested the water tonight, my ph was 8.0, ammonia and nitrite are 0, and nitrates are 200!

My next move is going to be to remove the bioballs completely and replumb the drains so that 75% of the water bypasses the refugium. Will this help, or should I be trying something else? I'd love to add a large angel to the tank, but know I cannot as long as the water is this bad. I use RO/DI water for changes, and my 215 reef has zero ammonia, nitrite and nitrates with a fuge thats plumbed the way I plan to replumb the other tank. It also has about 300 pounds of lr, though. Help!
 
If I read your post correct, you still have bio-balls in your system. If you want to drop your nitrates, you MUST remove the bio-balls. Whether you NEED to, with a FO tank, I don't know. Many, many fish stores still use bio-balls (or something like them) in their systems, because fish can tolerate nitrates more than ammonia or nitrites.

With bios in your system you have little chance of making progress on nitrates. Look through the fuge thread in this forum. Some REALLY nice (not to mention BIG) fuges in that thread. They made me want to set one up simply because they are so nice.

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1349443

nalbar
 
What test kit did you use for Nitrates?My API kit showed blood red,I freaked out and took sample to LFS that tested sample at 40 ppm( still high but much better).Test with another brand if you can or have a LFS verify your results.
 
Unless you're doing big water changes, you really don't have much there to remove nitrate, so it will build up. You have a little refugium, and not so much live rock (and live rock is not that fantastic a denitrafication medium anyway). So figure out some of the common methods of how to remove nitrate (dsb, macroalgae that grows vigorously, bigger skimmer helps a bit) and mod your system a bit. Just my opinion.
 
just my 2 cents
i used to clean tanks for a store
some of the nicest tanks i have seen had bio balls and tested 0
it seems anything old school is just cannon fodder latley
just wait live rubble will be out of favor in a few years and people will blame them for leching silica or something like that
if you can get the water going into your sump going to the bio balls after skimming and a filter sock
oh yeah enjoy the bashing i will soon recieve for not saying get rid of the bio balls
 
Wow. Some interesting opinions. As for the test kit, its a simple multi-test dip strup kit. It does however show my reef at 0 nitrates, which appears to be correct, so I'm not sure its the kit. I may try to add some lr, and I will also look for the sugar thread. Sounds kinda like what the old DAS systems used. Might work. I'll reconsider the bioballs also. I currently have three of the fom prefilter cuffs from the original drain pipes in the sump that I kept just for the bacteria in them, but I may take them out also. Any more suggestions are welcome!
 
Do you have a skimmer running your system? If not that might be something to look into. Not sure how much it will help reduce Nitrates but it will definitely benefit your system in removing a bunch of fish poop.

Doing that plus doing regular water changes would be the recommended way to reduce Nitrates.

Personally I would start doing that before dosing anything. Remember the solution to pollution is dilution.
 
All that has been mentioned is good advice, and if I may I'd like to add two things to the list of suggestions:

1. With regard to the deep sand bed, I decided against having a deep sand bed in the display tank because fish waste accumulates too quickly in sand in my opinion. Siphoning sand is usually a losing battle and stirs up nitrate. I siphoned all the sand out of the main display tank, opting for the barebottom display, and it quickly corallined over with the help of some Purple Up. I have powerhards positioned along the back wall angling down, hidden by rocks, and this pushes all the waste into piles where the water eddies along the front of the tank, where it is easily siphoned off. In my FOWLR, I am amazed at how quickly waste accumulates and am convinced that having sand in the main tank with more than just a few fish is an uphill struggle against waste accumulation.
2. With that in mind, a few of my smaller tanks have 10-15 gallon refugiums beside or below them, with 8-10" dsbs that have now become chaeto farms and copepod factories. But I think you might be more interested in the setup on my larger 125. It has a 55g sump with two approx. 5G rubbermaid trays full of sand. The drain tubes come down the sides of the sump and water flows over the sand trays before being pumped back up to the display tank by the return which is in the center of the tank. By putting the sand in rectangular trays, I minimize the likelihood of sand getting into my pumps. Havent had any problems and havent had any algae growth/nitrates since. Just one of many methods...may try combining this with the sugar technique. good luck
 
Well thats interesting! I do have a semi deep sand bed (about 4 inches of mixed finely crushed aragonite and southdown oolitic sand). I have almost no algae in the display, with only two small snails for control. In fact, since I added a couple peices of lr that someone gave me, they have remained largely algae free. I do know I have a lot of sediment in the bottom of the sump and I also have granules of nitrate absorbant that spilled out of a filter sock years ago. They're loose under the bioballs and occassionally clog up the intake cover of the return pump. Water changes seem to make little difference, but maybe I should just do more of them. Maybe the nitrate level is just so high I need to be more aggressive about bringing it down. I will try to rework the fuge per Melev's recommendations (heh heh, he's local to me, and built my sump for the my reef - he also gave me a personal lesson on how to plumb the sump, with only about 25% of the water flow going over the fuge).

Anyway, thanks as always for the suggestions!
 
<a href=showthread.php?s=&postid=12342809#post12342809 target=_blank>Originally posted</a> by bipolarbear


Doing that plus doing regular water changes would be the recommended way to reduce Nitrates.

Personally I would start doing that before dosing anything. Remember the solution to pollution is dilution.
Click to expand...

I agree 100%. Do some major water changes. The Cheato should be able to keep the tank maintained. I could be wrong but I do not think that Live Rock will do anything for your Nitrate problem as Nitrates are the final byproduct of the cycle.
I do not think you need to go as far as trying anything weird or unnatural (like adding sugar to your tank) to rid the system.

Just keep your equipment clean and do regular water changes.

-=E=-
 
Maybe I learned reef chemistry somewhere else, but live rock is the best natural denitrifier there is. It was the critical component that first allowed the keeping of corals in captivity. The anaerobic bacteria that resides in its interior consumes the nitrate that is produced by aerobic bacteria that resides on its surface. This is the basis of natural filtration.

You are describing the exact problem that is encountered when you have bioballs and inadequate rock. I'm willing to bet your problems could be solved simply by doubling the amount of rock in the tank and removing the bioballs from the sump. Increasing water changes will help, too.
 
True seapug, but live rock capabilities are quickly overwhelmed by over stocking. Most people overstock their tanks when the fish are compared to the amount of rock. Because the flow through the low oxygen areas is so low, it takes a LOT of rock.

By 'overstock', I don't mean people have to many fish, just that they have to many fish if they expect just the rock to do the nitrate to gas conversion.

I have 4 fish and 200 pounds of rock in my system. I would assume that would be enough rock, but even I make sure by having a skimmer to help remove protein.

Good point seapug.

nalbar
 
I hear ya-- It could be easily argued that every closed system marine aquarium with anything alive in it is overwhelmed, biologically. It requires a combination of factors for the water to remain habitable by livestock. Protien skimmers are great, but they don't denitrify. They simply remove some organics before they can be mineralized into nitrate. There's no doubt they do help, but nitrate will still be produced by other biological processes in the tank. That's where live rock and properly maintained deep sand beds make their contribution. What's left can usually be managed with a macroalgae refugium and/or regular water changes.
 
<a href=showthread.php?s=&postid=12346454#post12346454 target=_blank>Originally posted</a> by seapug
Maybe I learned reef chemistry somewhere else, but live rock is the best natural denitrifier there is. It was the critical component that first allowed the keeping of corals in captivity. The anaerobic bacteria that resides in its interior consumes the nitrate that is produced by aerobic bacteria that resides on its surface. This is the basis of natural filtration.

You are describing the exact problem that is encountered when you have bioballs and inadequate rock. I'm willing to bet your problems could be solved simply by doubling the amount of rock in the tank and removing the bioballs from the sump. Increasing water changes will help, too.
Click to expand...

100% agree you have an nowhere near enough live rock in the system to provide bacteria a place to colonize and denitrify the system.
you need 1.5-2lbs per gallon of good quality porous live rock.

sure fish can tolerate living in high nitrate water, but that would be like humans breathing in really really polluted air.
 
What about placement of the additional rock? Should / could some of it go in the sump, or should all of it go in the display? I really appreciate the advice. I guess I'd forgotten how helpful RC can be!:rollface:
 
Your bio-balls by themselves don't produce nitrates, they just become the preferred place for your bacteria bed to live if you have them. This is because it's a very aerobic environment. However, they may trap materials that might otherwise get removed via your skimmer. In a skimmerless system, there would be no more nitrates produced by bioballs than by live rock. In a system with a skimmer, it depends on what makes it to the skimmer versus what gets trapped. The amount of nitrates produced would be dependent on the amount of food added, being converted to ammonia, being converted to nitrite, being converted to nitrate. More live rock is another trap for decaying food, etc so you may not see an improvement. I don't think skimmers are necessarily good for removing dissolved nitrates, they're just good at removing some of the food and waste ( which is also food for something) that becomes nitrates.
 
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