Nitrate Control

RedLion

RedLion

AC Members
Aug 25, 2009
92
0
6
Houston, TX
Hey All,

Gotta question for you guys regarding nitrate levels! I have a 36 gallon tank thats been running for almost 6 months. I have about 36 pounds of live rock to help keep my parameters stable. I do a 10 percent water change weekly to keep things in check and use RO water from the LFS, but my nitrate levels won't go below 10 ppm and usually stay at a steady 20 ppm. I feed a small portion of seaweed daily and 1 cube of frozen Spirilina every other day. I have a tomato clownfish, blue hippo tang(medium size), 2 turbo snails, 5 little snails, red knobbed starfish, cleaner shrimp and coral banded shrimp. Is a steady Nitrate leve of 20 ppm acceptable for the long haul? If not, what action should be taken to reduce the nitrate levels to an undetecable level? Keep in mind my objective is to add a few more small fish to the tank. I want to maximize this little tanks potential:flamed:

Thanks guys,
Joey
 
The best long term solution for nitrate control is algal uptake. I highly suggest a refugium if that is possible. They also make small in-tank refugia that may help some. There are also other options, such as turf scrubbers, but that may or may not be easy in your situation. You haven't really described your setup in detail, though. Do you have a sump? Can you fit one, etc.?

Beyond that, the blue tang really needs a much larger tank. Also, while it isn't necessarily natural or optimal, 20 ppm of NO3- is still considered acceptable in most circumstances. However, with the solutions above, you can reduce that, as well. In addition to that, how often are you changing any mechanical filtration, if you have any?
 
I have an external powerfilter with mechanical, chemical and biological filtration (AquaClear 50). I change the media according to the manuafactuer's recommendations: Sponge filter is replaced every 2 months (with a rinse in between replacements months). Carbon replaced monthly and Biomass replaced every 3 months. I also have a CPR BakPak 2 Protein Skimmer with BioBale which I clean every 2 months, at least. I could probably do a sump, but I would rather avoid it. A small in-tank refugia may work for me, but I have little room to play with since its only a 36 gallon corner tank. The blue tang appears healthy, vibrant colors, active and eating well. If the tang's health or stress level changes will make arrangements for the fish to be placed in the appropriate environment. What do you think?
 
The main thing with the tang is that they like lots of swimming room--not something your tank is going to be able to provide. They are best left to much larger tanks, unfortunately. As far as replacing the media, I highly recommend you change the mechanical filter more often. Every 2 months is very inadequate under almost all circumstances. If you are experiencing a nitrate problem, changing this more often may be a bit help, in addition to the refugium. I also highly recommend looking into a sump where you can place a protein skimmer and/or a larger refugium to help you deal with the excess nitrogen. The refugium will be more effective at directly handling nitrate than a skimmer will, though.
 
My guess is the mechanical (sponge and carbon) and bio media (biomax cartridge)that came with that the AC filter is the cause of your problem. Think the biggest problem may be the sponge even though you are rinsing the sponge between change outs. I had a similar problem with sponges in my old Aquapod. I ditched the sponge and bought a huge bag of Poly-fill from Walmart (fabric section, its pillow stuffing) and I replace it once/twice per week. The bag is about $4 and it will last you forever. Just make sure to avoid the flame retardent stuff if your WM happens to carry that. You can buy the same stuff as Petco, Petsmart, etc but it will cost you a lot more for a lot less material. I have a AC filter as well and just lay a mat of the fill down on the bottom of the tray and then place a bag of Chemipure Elite on top.

I'm guessing your carbon may be a problem as well. A bag of carbon in a tank with larger fish will get exhausted pretty quickly and once its spent, nutrients will just leach right back out into your water. I would change the carbon twice per month or go buy some Chemipure Elite which will last you 2-3 months between changeouts. Also ditch the biomax cartridge, your LR is providing all the denitrifying bacteria your need. That little bag isn't doing much more (except probably trapping detritus).

A for refugium options w/out a sump. You could modify your existing AC filter into a HOB fuge. Lots of reefers have done this. I think an AC 50 might be a little small. Most use a 70 or 110. A 110 on that size tank would provide some nice flow as well. Speaking of flow, do you have enough in your tank to keep detritus off your LR? If not increase your flow with PHs or maybe upgrading your filter to the 110. Ever use a turkey baster to blow off your rocks? Trapped detritus in your LR may be part of the problem as well.

You're going to want to find a new home for that tang. They're swimmers and need lots of room.
 
Thanks guys. I am going to make a few changes and see if I can get those Nitrates down to undetecable levels. I plan on doing the following, so tell me what you think.

1.) Increase weekly water changes from 10% to 20% (with treated tap, using RO for only for top offs)
2.) Replace the mechanical spong every other week
3.) Replace the carbon every other week
4.) Clean my protein skimmer monthly

I will see where that gets me. If that still doesn't help I will do the following:

5.) Change the sponge to Poly-fill
6.) Replace the bio-media and carbon with Chemipure Elite

And if all else fails I will look into the refugium option. I am just trying to work with what I have at the moment. I have 2 powerfilters 1 being used with UV and the other just for water movement aimed over the rocks, each are rated at 160gph so I suspect I am getting at least 5-6x the water movement per hour, plus i am not accounting for the protein skmmer or the external power filter.
 
What are the nitrate concentrations from tap? Topping off with RO water and then going and performing 10-20% weekly water changes with tapwater isn't doing you any good--if anything, it is a waste of money. Step up to replacing and/or rinsing that sponge on a weekly basis, if not more. Carbon schedule sounds good and the water change schedule by itself does, but see my point on tapwater. You don't need to tear down the skimmer and clean it monthly, but you should be cleaning the neck and riser portion of the cup almost daily. I recommend a toothbrush to gently circle around the neck and get rid of any buildup. This accomplishes removal of buildup without disturbing the action of the skimmer. It should help it get more consistent skimming.
 
That's an excellent point! I have never measured my tap water for nitrate directly, always after it has been in the tank for sometime. I remember when I set it up I used treated tap and it read 0 for a couple weeks, so I suspect it has an undetectable level of nitrate in it I will check for Nitrite, Ammonia and Copper too while I am at it. I also get what your saying about tap water in general, even if it's a good water source (LFS says it is), over time certain undesireable chemical concentrations will build to unhealthy levels. But I was thinking that this fact is most important with topping off, since water changes remove water and replace it with the same quantity and subsequent concentrations which will therefore not add to the problem, it will cancel itself out. Thus resulting in almost no change in tap water chemical concentrations in the tank overall, right? If you don't agree I will stick to strict RO. I will follow directions on the sponge, carbon and clean the skimmer cup more often; I have been slacking on that bc I thought it was ok to let it go about a week or till the cup is about 3/4 full, I didn't think the process was degrading.
 
What's in the cup isn't as important (unless you are sensitive to the smell). What is important is that you break up some of the scum that develops on the inside of the neck. You don't want to completely clean it (i.e. squeaky clean) every time, just a quick brush with a toothbrush. Then, every month or so, or when the cup fills, take the whole thing off and clean it thoroughly. You just don't want to do that too often because it does interrupt performance for a while.

As far as your water change regimen is concerned, in theory, that is right. However, you don't know what else is in your tapwater. There could also be compounds created in your tank that aren't necessarily getting diluted that you are simply adding back during a water change. Don't ask me what exactly those may be specifically (organics are likely), but it is something to consider. There are a lot of variables out there, and I don't know if you are like me, but I like to reduce them as much as possible. If I can throw out one more unknown in all of this, I'm happy. JMO.
 
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