Keeping Nitrates Low Without Underfeeding

[dmweise]

I have been trying to find a good way to keep nitrates low without having to underfeed my fish. My nitrates stay at about 25 parts per million. The other parameters are fine:

Ammonia: 0 ppm
Nitrate: 25 ppm
Nitrite: 0 ppm
PH: 8.0
SG: 1.022
Temp: 78 F

I am running a EuroReef RS80. My tank is 90 gallons. I have a refugium setup with caeto and caulerpa growing. I feed my tank with a strip of algae that is four inches by two inches each day as well as two cubes of PE Mysis.

I have between 50 and 75 pounds of live rock in the tank. I am thinking about adding about 50 more pounds and getting a larger skimmer. Will that help keep Nitrates low?

Here's what I have in my tank:

Fish:
• Bicolor Angel (1)
•*Flame Angel (1)
• Lawnmower Blenny (1)
• Flame Hawkfish (1)
• Spotted Hawkfish (1)
• Pink Skunk Clown (2)
• Copperbanded Butterflyfish (1)
• Blue Green Chromis (2)
• Marine Betta (1)
• Dilectus Pseudochromis (1)
• Yellow Eye Kole Tang (1)

Invertibrates:
• Coral Banded Shrimp (1)
• Fire Shrimp (2)
• Arrow Crab (1) <--- in the refugium
• Long Tentical Anemone (1)
• Fighting Conch (2)
• Mexican Turbo Snails
• Turbo Snails
• Astrea Snails
• Hermit Crabs

Coral
• Toad Stool
• Kenya Tree
• Pom Pom Xenia
• Australian Duncans
• Frog Spawn Euphilia
• Scuba Steve Euphilia
• Torch Euphilia
• Zoanthids (Green)
• Zoanthids (Purple Death)
• Mushrooms (Green)
• Mushrooms (Watermelon)
• Alveopora

[recoiljpr]

Skimmer will help keep the nitrates lower, sure. What is your detrivore cleanup crew like? Bristle worms, scuds, Nassarius, and how many hermits?

I'm a huge believer on detrivores. I keep very few algae cleaners in my tank, but I stock detrivores very heavily. I feed 1+ cubes of frozen and a good 6 pinches of pellets. I also add every other day live brine/artermia and I dose phyto every other day.

My nitrates usually stay around 5 (salifert tests). I've found that when you have a lot of detrivores, they will eat all of the left over food before it has a chance to decompose and cause nitrates.

In my 65 for example I have 10 Nassarius, 2 emerald crabs, 10 blue legged hermits, 20+ micro stars and I added the Detrivore kit from inland aquatics (added stars, scuds, bristle worms, etc).

I love to feed my tank, as I love seeing how the animals react, and i'd rather have fat fish. To do that in a closed system, you have to be able to get rid of the excess food. Detrivores are a good way to do that.

Another good thing about going heavily on the detrivores is that you can then go light on the algae cleaners because they take care of the nutrients before they start causing a lot of problems.

[fishypets]

Why do you think you need to lower your NO3?

[aquasport24]

I don't think you overfeed, but you may have overload the livestock (13 fishes). How often do you do water change? Just have to increase WC (water change) if you plan to keep all the fishes and add more flow.

[Kyle46N]

Yeah, I was thinking there might be too many fish. Like mentioned, more water changes. Detrivores are a good idea, but I'm not sure if your extra food is the problem. I think it may be just too much fish poo.

[Bill S]

Clean up crew - including detrivores - won't help your nitrates much. Nearly all of what they clean up, is excreted and then also goes thru the cycle.

More live rock also won't help you - because Nitrates are the ending process of the ammonia cycle. You CAN lock nitrates up in algae - which is what you are doing with your fuge. The only way to export nitrates is as nitrogen - thru algae production which you then thin and throw out, as nitrogen gas, or via direct export with water changes. You can export via nitrogen gas with a deep sand bed, or a di-nitrifying system. More clean up won't help. More skimming can help.

As noted above, 25ppm really isn't that bad. If you were to get long-time reefers to tell the truth, you would find the average nitrate levels to be somewhat higher than is generally claimed. Funny how that works.

[CoryDude]

If you were to get long-time reefers to tell the truth, you would find the average nitrate levels to be somewhat higher than is generally claimed. Funny how that works.

Amen to that Bill. We need to start a section in Maast where we can anonymously post our REAL tank stats.

25ppm is not too bad, like Bill said. A larger skimmer may help with catching proteins before the turn into ammonia, which may impact your NO3 levels down the road. Personally I use a bio-denitrator on my 90 gallon to keep NO3 around 5ppm. But, I don't think it will help with a bioload such as yours.

A Hiatt system could work. I'm just setting mine up on a 60 gallon, but Bill can give you more tips since he's been using his longer.

[ballardjr2000]

nitrates 25 not too bad..mine stay around 10 even with water changes. i would say a skimmer or more growth of alge to export. some people run a turf filter. or just get a really nice LARGE PROTEIN skimmer. will help some but as stated 25 isn't bad persay they many have them higher than stated.

[dmweise]

I think I will get a larger skimmer to help things out. Right now I use a filter sock and I really do not like it. I have to replace it once every two weeks.

I have bristles worms, probably 20+ nassarius snails and 15+ hermits. I should get more. My boyfriend keeps saying that I should get more. I just think he wants me to buy cheaper things as well. Haha. I am not too sure what a scud is, other than the ammunition. I have a few small star fish that have hitch hiked, but not many.

Okay, good, I'm not overfeeding. I use a Tetra test.

I agree. Feeding time is one of my favorite times, especially since I got my marine betta.


Skimmer will help keep the nitrates lower, sure. What is your detrivore cleanup crew like? Bristle worms, scuds, Nassarius, and how many hermits?

I'm a huge believer on detrivores. I keep very few algae cleaners in my tank, but I stock detrivores very heavily. I feed 1+ cubes of frozen and a good 6 pinches of pellets. I also add every other day live brine/artermia and I dose phyto every other day.

My nitrates usually stay around 5 (salifert tests). I've found that when you have a lot of detrivores, they will eat all of the left over food before it has a chance to decompose and cause nitrates.

In my 65 for example I have 10 Nassarius, 2 emerald crabs, 10 blue legged hermits, 20+ micro stars and I added the Detrivore kit from inland aquatics (added stars, scuds, bristle worms, etc).

I love to feed my tank, as I love seeing how the animals react, and i'd rather have fat fish. To do that in a closed system, you have to be able to get rid of the excess food. Detrivores are a good way to do that.

Another good thing about going heavily on the detrivores is that you can then go light on the algae cleaners because they take care of the nutrients before they start causing a lot of problems.

[dmweise]

Usually when I mention that my nitrates stay at about 25 ppm other reefers that I've talked to scoff and start telling me that I don't care about my fish.


Why do you think you need to lower your NO3?

[dmweise]

I do weekly water changes of 15 gallons. I think I need a more powerful return pump. Right now I am using a Mag 350. I also have two Tunze 6025s in the tank to add extra current. I change the flow of the power heads occasionally to help move things around that may have settled, but not too often.


I don't think you overfeed, but you may have overload the livestock (13 fishes). How often do you do water change? Just have to increase WC (water change) if you plan to keep all the fishes and add more flow.

[dmweise]

It is kind of weird, even when I only had a few fish my nitrates stayed at about 25. I used to just have these:

• Bicolor Angel (1)
• Lawnmower Blenny (1)
• Flame Hawkfish (1)
• Pink Skunk Clown (2)
• Copperbanded Butterflyfish (1)
• Blue Green Chromis (2)

I added these in the past two months:

• Flame Angel (1)
• Spotted Hawkfish (1)
• Marine Betta (1)
• Dilectus Pseudochromis (1)
• Yellow Eye Kole Tang (1)

Since adding the others I have seen little to no rise in nitrates each week. I was probably feeding too much before and now the feeding and poop making have equaled out thus keeping the nitrate level the same.


Yeah, I was thinking there might be too many fish. Like mentioned, more water changes. Detrivores are a good idea, but I'm not sure if your extra food is the problem. I think it may be just too much fish poo.

[recoiljpr]

I have bristles worms, probably 20+ nassarius snails and 15+ hermits. I should get more. My boyfriend keeps saying that I should get more.

That's actually a pretty good #. You can try and get more, but being that most of us have less then 50% of the sandbed open, you have an adequate crew IMO. Do you turn off your pumps,etc when you feed? Doing that will also help keep the food with the fish, and not have so much be caught and wasted in the rocks.



I am not too sure what a scud is, other than the ammunition. I have a few small star fish that have hitch hiked, but not many.

A scud is a gammarus shrimp, good little detrivore, and the fish like to pick at them as well.

That being said though, as others have stated 25 isn't horrible and you shouldn't need to do anything drastic like huge water changes (the only sure fire way to get nitrates out quickly).

[dmweise]

I have been wanting to thicken up my sand bed. Currently it is about 1 to 1.5 inches thick. My refugium sand bed is a good 4 to 5 inches thick. Once the caeto and caulerpa take hold it should help out a lot.

I think a bigger skimmer would be great. It'd help decrease my reliance on filter socks. I have been thinking about creating a bio-ball section in my sump but have heard mixed feelings about them.

I had a feeling that folks were just busting my balls about the nitrates being high.


Clean up crew - including detrivores - won't help your nitrates much. Nearly all of what they clean up, is excreted and then also goes thru the cycle.

More live rock also won't help you - because Nitrates are the ending process of the ammonia cycle. You CAN lock nitrates up in algae - which is what you are doing with your fuge. The only way to export nitrates is as nitrogen - thru algae production which you then thin and throw out, as nitrogen gas, or via direct export with water changes. You can export via nitrogen gas with a deep sand bed, or a di-nitrifying system. More clean up won't help. More skimming can help.

As noted above, 25ppm really isn't that bad. If you were to get long-time reefers to tell the truth, you would find the average nitrate levels to be somewhat higher than is generally claimed. Funny how that works.

[dmweise]

I think that's a great idea. That would help us gather some good "average" parameters that folks can go off of instead of what the test kit boxes say.

I haven't had anything die and haven't had any problems with algae blooms. I have a UV sterilizer running to counter any microbe problems.

Hmm, bio-denitrator. I haven't heard of such a contraption. As you mentioned it probably wouldn't do much good in my tank since I have a good colony of fish.

I think a larger skimmer is the way to go.


Amen to that Bill. We need to start a section in Maast where we can anonymously post our REAL tank stats.

25ppm is not too bad, like Bill said. A larger skimmer may help with catching proteins before the turn into ammonia, which may impact your NO3 levels down the road. Personally I use a bio-denitrator on my 90 gallon to keep NO3 around 5ppm. But, I don't think it will help with a bioload such as yours.

A Hiatt system could work. I'm just setting mine up on a 60 gallon, but Bill can give you more tips since he's been using his longer.

[dmweise]

That's three+ votes for a bigger skimmer. I should have posted earlier. AquaTek just had their annual sale. Oh well, they already get half my pay check (all, slightly exaggerating).


nitrates 25 not too bad..mine stay around 10 even with water changes. i would say a skimmer or more growth of alge to export. some people run a turf filter. or just get a really nice LARGE PROTEIN skimmer. will help some but as stated 25 isn't bad persay they many have them higher than stated.

[recoiljpr]

Clean up crew - including detrivores - won't help your nitrates much. Nearly all of what they clean up, is excreted and then also goes thru the cycle.

Bill, here is my line of reasoning with the detrivores/nitrates relationship. We know that most marine life does not have the most effective metabolism.

For the sake of argument lets say that only 50% of ingested material gets used in an organisims metabolic process (breathing, swimming, etc), the other 50% is excreted as waste. In my thinking, it's a simple #'s game in that the more times a given food item is reprocessed, only half remains.

So if a fish eats 1 ounce of food, it would excrete .5 ounces in waste. A large detrivore like a big star, etc eats that waste, and it would then excrete .25 ounces in waste of the original 1. Then, amphipods and small stars come in, eat that waste and escrete .125 ounces in waste. Copepods , etc then come in and eat that waste, leaving .06 ounces of waste. Filter feeders such as sponges, tube worms, etc eat that waste, leaving .03 ounces, etc, etc.

That is why I feel micro-detrivores are too commonly overlooked in a system. They are a good way to ensure waste is reprocessed multiple times.

Granted, all of this is what I think, I have no studies proving it; I could be totally worng. :-)

[dmweise]

Sounds logical to me. I don't think that you can ever have too many detrivours. I've always said 'well you can never have too many snails'. My saying was more geared towards turbos. I did not even think to apply it to nassariuses.


Bill, here is my line of reasoning with the detrivores/nitrates relationship. We know that most marine life does not have the most effective metabolism.

For the sake of argument lets say that only 50% of ingested material gets used in an organisims metabolic process (breathing, swimming, etc), the other 50% is excreted as waste. In my thinking, it's a simple #'s game in that the more times a given food item is reprocessed, only half remains.

So if a fish eats 1 ounce of food, it would excrete .5 ounces in waste. A large detrivore like a big star, etc eats that waste, and it would then excrete .25 ounces in waste of the original 1. Then, amphipods and small stars come in, eat that waste and escrete .125 ounces in waste. Copepods , etc then come in and eat that waste, leaving .06 ounces of waste. Filter feeders such as sponges, tube worms, etc eat that waste, leaving .03 ounces, etc, etc.

That is why I feel micro-detrivores are too commonly overlooked in a system. They are a good way to ensure waste is reprocessed multiple times.

Granted, all of this is what I think, I have no studies proving it; I could be totally worng. :-)

[dmweise]

That's a good idea. I can turn off my powerheads when feeding. The return pump is not super flowing. I'll try that out.

Ah a shrimp. My hawkfish would eat them. I had two cleaner shrimp but they lasted about a day.


That's actually a pretty good #. You can try and get more, but being that most of us have less then 50% of the sandbed open, you have an adequate crew IMO. Do you turn off your pumps,etc when you feed? Doing that will also help keep the food with the fish, and not have so much be caught and wasted in the rocks.



A scud is a gammarus shrimp, good little detrivore, and the fish like to pick at them as well.

That being said though, as others have stated 25 isn't horrible and you shouldn't need to do anything drastic like huge water changes (the only sure fire way to get nitrates out quickly).

[Ping]

Your DSB fuge should not have any vegetation or rock covering the sand if you want it to work properly. The sand needs moderate to strong current for advection to take place; this speeds up the ammonia cycle. A DSB may take up to two months to achieve its full processing potential. The DSB fuge does not need detrivours and especially not crabs.

Crabs consume the micro-life so important for breaking down the "detritus". More than two or three crabs and too many non-microscopic detrivores will devour the life in live sand. Just because sand is in a system does not mean it is actually alive. If there is food in the rocks, it wont take long for a few detrivores to find and consume it.

Your bio load is too high and water changes will help. "Dilution is the solution to pollution".

Macro algae only remove a small amount of NPK as it grows. It will not lower N like a properly set up DSB will. Macro algae provide does lower the nitrates a small amount, and is excellent home for the plankton and pods we desire in our systems.



Again, too many critters eating off and from the sand bed and live rock will decimate the micro life in and on both that we should strive for.

[Ping]

Micro detrivores and decomposers are what we want. They can be seen with a microscope. Each trophic level is only 10% efficient through metabolism, the remaining 90% is waste.

[OrionN]

If you add a live sandbed, this will keep your nitrate down to 0. If you choose to do this, make sure you seed it with a variety of sand bed organism.

[dmweise]

I have a live sand bed. I think it just is not deep enough. It is only about an inch deep in the display tank. I made the mistake of putting in crushed coral on top of my sand bed when I had some jawfish. I am in the process of removing the crushed coral but it is a fairly slow process. Once it has been removed I will increase my sand bed depth to about 2 or 3 inches.


If you add a live sandbed, this will keep your nitrate down to 0. If you choose to do this, make sure you seed it with a variety of sand bed organism.

[Bill S]

2-3" sand bed won't do you any good. Either stick with a 1" or less sand bed, or you'll have to go to a deep sand bed.

[aquasport24]

You can add a RDSB (remote deep sand bed) some where in the sump or connect to the sump somehow.

[Neptune@gabesfish]

Sorry if this has already been answered but is anything wrong with your tank? Are animals dieing or close to death or are you judging your tank by your test scores..25ppm most long time reefers I know would love to have those ppms

[OrionN]

I keep 2-3 inches sand bed and 8-12 inches sand bed before. They works the same for me. right now I have a 2-3 inches sand bed in my 30 g cube and my nitrated is always 0. I do keep a very live sand bed with very active worms snails and many small crustacean in it. My experience strongly suggested that a 2-3 inches sand be will works very well indeed. A few years ago, Reefs.org did a study on various dept and size of sand needed to be use to process nutrients. If I remember right, coarse sand/crush corals at 2-3 inches did very well. I will try to see if I can pull up this study. It was very well design study with control.

[OrionN]

Here are the article. You can read and make your own conclusion
http://www.advancedaquarist.com/2005/7/aafeature/view?searchterm=sandbed
http://www.advancedaquarist.com/2005/6/aafeature/view?searchterm=sandbed

[OrionN]

I just re-read these two articles. I highly recommended it to anyone who want to use a sandbed. It is slightly different than what I remembered from my first reading several years ago (2005).

[dmweise]

Sorry if this has already been answered but is anything wrong with your tank? Are animals dieing or close to death or are you judging your tank by your test scores..25ppm most long time reefers I know would love to have those ppms

Nope, thing is wrong with them. They are all happy and eating. I rarely have any deaths in the tank. Even my coral is doing great.

[Ping]

Sorry to hijack this thread,
OrionN, I would argue against the validity and results from both of those studies. I reread them and the only thing they got right is that we do not need a plenum.

[OrionN]

Ping,
You can reach your own conclusion. I just want to point out the I disagree with Bill statement that 2-3 inches sand bed does no good. This was why I look up this study because I read it, and remember it from years ago. I think that 2-3 inches sand bed does plenty of nitrogen filtration. This study and my experiences confirm this, along with seen plenty of Nitrogen bubbles in the sand bed. I know that my moderate stocking tank with a 2-3 inches sand bed always have essentially close to not detectable Nitrates using hobby test kits.

[Paul28]

This is a very good Page on DSB, http://www.reef-eden.net/DSBs.htm (http://www.reef-eden.net/DSBs.htm) the sand bed in my tank is around 4 years old and is 4 to 5 inches great layers of life in it

[Paul28]

o yeh my clean up crew is maybe 4 nas snails and 2 turb snails and 2 herms, the life on my rocks and sand bed do all the cleaning

[Paul28]

you know whats a neat little trick get a silverside fish stick a toothpick in its head and in the lover body so nothing can pull it off the toothpicks put it in your sand bed right at lights out wait maybe 15 min then get a flash light Wow tons of baby brittlestars and bristleworms will be all over it were you cant even see the fish by the morning its gone and maybe 1 toothpick will be pulled under a rock half way its real neat :)

[Bill S]

Minh,

Thanks for the links. I finally got around to reading.

I guess I'm guilty of doing what I hate: repeating mantras heard over and over again in the industry, that may or may not be well founded.

As most know, I'm a molecular biologist by education - I should know better.

I do know that, based upon my experience with sand fine beds, that once you get under the first about 3/4", they quickly become anaerobic.

[corydrysdale]

This may be in the wrong place, but when i wanted to start a refugium, many people pointed me in the direction of Miracle mud. It was in my fuge with chaeto and calerpa for over a year. Everything grew well with tons of micro organisms. Nitrates were still in the 40's on my 125 gallon tank. Even though i followed most suggestions to a "T" not sure i got the best deal i could have gotten. Currently im going bare bottom fuge with just chaeto growing. Stocking copepods and amphipods there. That miracle mud was a bugger to clean out of my sump!!

[H2Ochem]

The great sand bed debate. I love this one. Run as many experiments as you want and apply the biological and chemistry theory as you see fit. In the end "what works for one may not for another." There are just too many factors involved in a closed system to say what "one" method is the best. Light cycle, temp, Ph, alk, etc, etc ....all are factors that apply to bacterial lag, expotential, and stationary phases.

Nitrate at 25ppm means your biological filtration is working.Could it be better, sure. If your system shows no adverse effects at that level...your good.