Importance Of Controlling Nitrate In Saltwater Tank?

Luciferene

Valued Member
Messages
191
Reaction score
45
Points
63
Experience
5 to 10 years
Hi, I'm wondering why nitrate control is so much more sensitive in a saltwater tank vs a freshwater tank?

I'm wondering if it's just the corals that are sensitive to nitrates or even the fish are as well. Because I've read that for saltwater tank, you want the denitrification process to be in place for a tank to be called cycled. Where as for freshwater tank once nitrates appear and ammonia and nitrite are 0, you assume the tank is cycled.

Thank you!
 

Ernest Sacco

Well Known Member
Messages
632
Reaction score
208
Points
88
Experience
5 to 10 years
Hi, I'm wondering why nitrate control is so much more sensitive in a saltwater tank vs a freshwater tank?

I'm wondering if it's just the corals that are sensitive to nitrates or even the fish are as well. Because I've read that for saltwater tank, you want the denitrification process to be in place for a tank to be called cycled. Where as for freshwater tank once nitrates appear and ammonia and nitrite are 0, you assume the tank is cycled.

Thank you!
I'm relatively new to salt water only running my first tank for a little over 6 months...corals are very sensitive to fluctuations of any type and high nitrates are not good for them....fish are also sensitive.....it really comes down to how ammonia and the nitrogen cycle comes to effect the ph which can have an effect on the specific gravity etc....basically a salt water system has a lot more moving parts and if one thing goes out of whack the whole thing grinds down
 

Lorekeeper

Well Known Member
Messages
2,586
Reaction score
1,688
Points
158
Experience
4 years
It's not any more important, really. Nitrates are bad in both FW and SW, for nearly the same reasons.

Corals, inverts, and fish are all sensitive to nitrates, in both Fresh and Saltwater. It's just in a SW tank, the majority of the creatures in your tank tend to be either coral or inverts, which are more susceptible to nitrate than fish are. I've always just waited until the tank can cycle a few PPM of ammonia in a day for both my FW and SW tanks, and haven't had much issue. Of course, wait until all the dead matter has decomposed off the LR as well.
 
  • Thread starter
  • Thread Starter
  • #4

Luciferene

Valued Member
Messages
191
Reaction score
45
Points
63
Experience
5 to 10 years
I'm relatively new to salt water only running my first tank for a little over 6 months...corals are very sensitive to fluctuations of any type and high nitrates are not good for them....fish are also sensitive.....it really comes down to how ammonia and the nitrogen cycle comes to effect the ph which can have an effect on the specific gravity etc....basically a salt water system has a lot more moving parts and if one thing goes out of whack the whole thing grinds down
Yea, it did seem like corals had the biggest issue with nitrate from the threads I've read.

It's not any more important, really. Nitrates are bad in both FW and SW, for nearly the same reasons.

Corals, inverts, and fish are all sensitive to nitrates, in both Fresh and Saltwater. It's just in a SW tank, the majority of the creatures in your tank tend to be either coral or inverts, which are more susceptible to nitrate than fish are. I've always just waited until the tank can cycle a few PPM of ammonia in a day for both my FW and SW tanks, and haven't had much issue. Of course, wait until all the dead matter has decomposed off the LR as well.
Makes sense, I keep lower nitrate for my shrimp tank as well. Now the whole thing about denitrifying bacteria, is it because SW is harder to do water changes compared to FW, since nitrate can be removed easily via WC? I had SW tank with Tomato Clowns while back and it was a pain to do WC trying to get all the salt and what not added correctly.

I'm not intending on getting back to Saltwater yet, but do media like Seachem Matrix really work for holding denitrifying bacteria?
 

stella1979

Moderator
Messages
7,494
Reaction score
9,624
Points
608
Experience
5 to 10 years
Yea, it did seem like corals had the biggest issue with nitrate from the threads I've read.


Makes sense, I keep lower nitrate for my shrimp tank as well. Now the whole thing about denitrifying bacteria, is it because SW is harder to do water changes compared to FW, since nitrate can be removed easily via WC? I had SW tank with Tomato Clowns while back and it was a pain to do WC trying to get all the salt and what not added correctly.

I'm not intending on getting back to Saltwater yet, but do media like Seachem Matrix really work for holding denitrifying bacteria?
Denitrification can be handled by certain medias like Matrix, but you have to wait a very long time for anaerobic bacteria to grow, so media isn't always the first choice. I do use Matrix in my filter though, but I also rely on a small refugium that is also in the filter. Skimmers and refugiums are also for nutrient reduction. So, why for all of this? Well, with a well stocked tank, even with regular water changes, do you often have nitrates steady and under 5ppm? Many corals will not tolerate nitrates much higher, but then again, there are some that do. Like everything, the hobby can be as hard as you make it. A fish only tank can have higher nitrates, but wouldn't you want shrimp, anemones, starfish, and corals???? Most of us do.
 
  • Thread starter
  • Thread Starter
  • #7

Luciferene

Valued Member
Messages
191
Reaction score
45
Points
63
Experience
5 to 10 years
Denitrification can be handled by certain medias like Matrix, but you have to wait a very long time for anaerobic bacteria to grow, so media isn't always the first choice. I do use Matrix in my filter though, but I also rely on a small refugium that is also in the filter. Skimmers and refugiums are also for nutrient reduction. So, why for all of this? Well, with a well stocked tank, even with regular water changes, do you often have nitrates steady and under 5ppm? Many corals will not tolerate nitrates much higher, but then again, there are some that do. Like everything, the hobby can be as hard as you make it. A fish only tank can have higher nitrates, but wouldn't you want shrimp, anemones, starfish, and corals???? Most of us do.
Could you explain a little bit about a refugium? I can't get my head around refugium, and I thought it was supposed to be in a sump. And yea under 5ppm is pretty hard to keep, unless I'm well understocked. I was thinking if I come back I would only to FOWLR with Ocellaris Clowns, since my old tank with Tomato Clowns, Anemones, Shrimps, Gobies, etc was way too hard to keep up with. But then MTS's side symptom is trying to have more species

Also do same type of HOB get used for saltwater as freshwater? I would think there's no difference, but just in case there is.

By the way, thank you everyone for the input, I'm learning a lot already.
 

stella1979

Moderator
Messages
7,494
Reaction score
9,624
Points
608
Experience
5 to 10 years
Yep, I use an Aquaclear 70 HOB on my 20g long reef tank, and that leads into your question about refugium, (aka, fuge.) A refugium is simply a place where macroalgae is grown, usually chaetomorpha, (chaeto). Tank water will flow through the fuge and chaeto will absorb nitrates and phosphates to aid in growth. As the chaeto grows, some of it is removed to make room for more growth. Large refugiums in sumps may also hold live rock rubble and or a deep sand bed. My fuge is in the HOB though. We modified it with some baffles and grates inside so water first passes through a floss pad, then through biomedia before flowing through chaeto for nutrient export. I just tossed some chaeto today as it had overgrown it's space. The chaeto needs a plant light to grow, so we have a small one over the HOB.
 

Nart

Well Known Member
Messages
3,135
Reaction score
4,386
Points
298
Experience
5 to 10 years
I won't get way too in depth. But it depends what your goal is with the reef tank that will determine what water parameters you are able to keep it at.

Typically with reef tanks geared towards accelerated growth patterns and ran with high flow and high light... they can keep their Nitrates relatively high. Those reefers will generally have a very high Alkalinity, Calcium, and Magnesium value as well. Number wise it can look something like this, Alk 12, Calcium 450, Mag 1380, Nitrates 20+

Normal reef tanks with good lighting and good flow... and steady coral growth, their numbers can look something like this, Alk 9, Calcium 425, Mag 1300, Nitrates 5.

Nitrates and Alkalinity go hand in hand.
Corals actually utilize light, trace elements, and nutrients (nitrates, fatty amino acid, food particles, etc...) to grow.
 
  • Thread starter
  • Thread Starter
  • #11

Luciferene

Valued Member
Messages
191
Reaction score
45
Points
63
Experience
5 to 10 years
Yup, same type of filters get used. I've got a TopFin HoB on my 5.5 gallon right now, actually.
Your 5.5 gallon has no sump right? Isn't it hard to keep the parameters in small tank like that?
Yep, I use an Aquaclear 70 HOB on my 20g long reef tank, and that leads into your question about refugium, (aka, fuge.) A refugium is simply a place where macroalgae is grown, usually chaetomorpha, (chaeto). Tank water will flow through the fuge and chaeto will absorb nitrates and phosphates to aid in growth. As the chaeto grows, some of it is removed to make room for more growth. Large refugiums in sumps may also hold live rock rubble and or a deep sand bed. My fuge is in the HOB though. We modified it with some baffles and grates inside so water first passes through a floss pad, then through biomedia before flowing through chaeto for nutrient export. I just tossed some chaeto today as it had overgrown it's space. The chaeto needs a plant light to grow, so we have a small one over the HOB.
I have Aquaclears as well and I'm not sure how you got around to getting a fuge in there. I guess it's like keeping plants and moss ball to compete with algae or other problems due to having extra nutrients.

Do you turn down your flow on AC? I usually aim for 8-10x flow which is why I use AC50 for one of the 20H I have. Or does one need stronger flow for saltwater?
I won't get way too in depth. But it depends what your goal is with the reef tank that will determine what water parameters you are able to keep it at.

Typically with reef tanks geared towards accelerated growth patterns and ran with high flow and high light... they can keep their Nitrates relatively high. Those reefers will generally have a very high Alkalinity, Calcium, and Magnesium value as well. Number wise it can look something like this, Alk 12, Calcium 450, Mag 1380, Nitrates 20+

Normal reef tanks with good lighting and good flow... and steady coral growth, their numbers can look something like this, Alk 9, Calcium 425, Mag 1300, Nitrates 5.

Nitrates and Alkalinity go hand in hand.
Corals actually utilize light, trace elements, and nutrients (nitrates, fatty amino acid, food particles, etc...) to grow.
Ah I see, I find planted tank complicated with the lightings and ferts, and reef tank feels like it's on a level above that. Now is Alkalinity synonymous with KH? I guess it sounds like you are overdosing on nutrients for faster growth. I'm wondering how that doesn't cause algae blooms, is there a way that those are directed only to the corals?

If I do start a SW tank, I'll probably have to start with FO or FOWLR before going to reef. Whole idea of scaping reef tank also scares me.
 

stella1979

Moderator
Messages
7,494
Reaction score
9,624
Points
608
Experience
5 to 10 years
I have Aquaclears as well and I'm not sure how you got around to getting a fuge in there. I guess it's like keeping plants and moss ball to compete with algae or other problems due to having extra nutrients.

Do you turn down your flow on AC? I usually aim for 8-10x flow which is why I use AC50 for one of the 20H I have. Or does one need stronger flow for saltwater?
It is quite easy to mod the AC. I'd be glad to help, but there are different ways of going about it, so you might want to watch a few videos then come back with any questions.

One does need higher flow in saltwater, generally 10-20x, or even higher for some of the high tech tanks. Just think of those ocean currents. Flow is not only accomplished by a filter though so in tank pumps, powerheads or wavemakers are used. I do slow the flow through the AC in order to give the water longer contact time with the chaeto. My HOB is an AC70, but we replaced the impeller with one meant for an AC30.

Another example of the flow needed in saltwater.... My salty qt is 5g, and has an AC20 running on high as well as a very small nano pump in the tank.
 

Lorekeeper

Well Known Member
Messages
2,586
Reaction score
1,688
Points
158
Experience
4 years
Your 5.5 gallon has no sump right? Isn't it hard to keep the parameters in small tank like that?

I have Aquaclears as well and I'm not sure how you got around to getting a fuge in there. I guess it's like keeping plants and moss ball to compete with algae or other problems due to having extra nutrients.

Do you turn down your flow on AC? I usually aim for 8-10x flow which is why I use AC50 for one of the 20H I have. Or does one need stronger flow for saltwater?

Ah I see, I find planted tank complicated with the lightings and ferts, and reef tank feels like it's on a level above that. Now is Alkalinity synonymous with KH? I guess it sounds like you are overdosing on nutrients for faster growth. I'm wondering how that doesn't cause algae blooms, is there a way that those are directed only to the corals?

If I do start a SW tank, I'll probably have to start with FO or FOWLR before going to reef. Whole idea of scaping reef tank also scares me.
No sump. Small tanks are a bit touchier than larger tanks are, but I just integrate it into my routine. I get up in the mornings, make coffee, brush my teeth, and then check the water level. If it's below the mark I made on the glass with a sharpie, I'll usually top it off. When I get home, I check the tank to make sure nothing's closed up or looking mad. If it is, I'll check the water. If not, I check the water every few days, just to make myself feel better about it.

I'd do the majority of that with any tank though, fresh or salt. And while it's true that pico saltwater tanks are a bit more tricky than most setups (other than maybe sensitive brackish tanks), they're easily learned. The same things apply to a 2.5G pico tank that apply to a 2000G tank. Keep your levels in check, keep your water topped off, and make sure everyone's happy.
 
  • Thread starter
  • Thread Starter
  • #14

Luciferene

Valued Member
Messages
191
Reaction score
45
Points
63
Experience
5 to 10 years
It is quite easy to mod the AC. I'd be glad to help, but there are different ways of going about it, so you might want to watch a few videos then come back with any questions.

One does need higher flow in saltwater, generally 10-20x, or even higher for some of the high tech tanks. Just think of those ocean currents. Flow is not only accomplished by a filter though so in tank pumps, powerheads or wavemakers are used. I do slow the flow through the AC in order to give the water longer contact time with the chaeto. My HOB is an AC70, but we replaced the impeller with one meant for an AC30.

Another example of the flow needed in saltwater.... My salty qt is 5g, and has an AC20 running on high as well as a very small nano pump in the tank.
I'll find some videos to watch, and if you have any links I would appreciate the info. I guess if I decide on getting a SW tank, I'll ask you more about it. I might even try a fuge for a high fert planted tank, even though I'm sure I can do without, I would like to entertain the idea.

Make sense, currents can be quite powerful in the ocean, I guess it would be species dependent though. I might try the impeller change, I needed more room for media in my AquaClear, but upgrading was going to be too high of a flow.

No sump. Small tanks are a bit touchier than larger tanks are, but I just integrate it into my routine. I get up in the mornings, make coffee, brush my teeth, and then check the water level. If it's below the mark I made on the glass with a sharpie, I'll usually top it off. When I get home, I check the tank to make sure nothing's closed up or looking mad. If it is, I'll check the water. If not, I check the water every few days, just to make myself feel better about it.

I'd do the majority of that with any tank though, fresh or salt. And while it's true that pico saltwater tanks are a bit more tricky than most setups (other than maybe sensitive brackish tanks), they're easily learned. The same things apply to a 2.5G pico tank that apply to a 2000G tank. Keep your levels in check, keep your water topped off, and make sure everyone's happy.
I found nano tanks for freshwater to also be pretty demanding. But yea once you get in the routine, I guess it isn't too bad. How often do you test for the parameters to see if there's any swing?
 

Lorekeeper

Well Known Member
Messages
2,586
Reaction score
1,688
Points
158
Experience
4 years
I'll find some videos to watch, and if you have any links I would appreciate the info. I guess if I decide on getting a SW tank, I'll ask you more about it. I might even try a fuge for a high fert planted tank, even though I'm sure I can do without, I would like to entertain the idea.

Make sense, currents can be quite powerful in the ocean, I guess it would be species dependent though. I might try the impeller change, I needed more room for media in my AquaClear, but upgrading was going to be too high of a flow.


I found nano tanks for freshwater to also be pretty demanding. But yea once you get in the routine, I guess it isn't too bad. How often do you test for the parameters to see if there's any swing?
I test every few days, or more often after an addition. I'd probably do about the same for a large tank .

For Salinity, just mark the water line with a sharpie and top off anytime it gets lower than that mark.
 
  • Thread starter
  • Thread Starter
  • #17

Luciferene

Valued Member
Messages
191
Reaction score
45
Points
63
Experience
5 to 10 years
Well, I looked a little bit at videos this morning, but didn't find a good one. There's a thread about it though!

Diy Aquaclear Refugium
Aw thank you, the thread is very informative, including your tip!

I test every few days, or more often after an addition. I'd probably do about the same for a large tank .

For Salinity, just mark the water line with a sharpie and top off anytime it gets lower than that mark.
Sounds similar to how I do it for my FW tanks, you probably have more parameters to check for though. And you use RO/DI water to top it off right?
 
Toggle Sidebar

Aquarium Calculator

Follow FishLore!





Top Bottom