Good Nitrate to Phosphate ratio for a reef tank?

[Reefahholic]

Hello!

Over the years this has been one of my favorite subjects. A while back I noticed my tanks doing a lot better with more NO3 than PO4.

When the NO3 matched the PO4 on the lower side the tank begin to grow hair algae in the sump, and dark brown algae on the rocks, overflow box, sand-bed and glass.

First let’s look at those low numbers. PO4 was down to 0.02-0.03ppm and NO3 was 1ppm.

As I bumped the the NO3 up to 3ppm...the algae begin to decrease. It continued to decrease even more as I slowly bumped it to 6ppm. Right now I’m holding it at 10ppm and the tank looks great.

I also increased the PO4 to 0.07ppm. This really got me thinking about the Red Field Ratio. Off the top of my head I think I heard you’re supposed to have 16 NO3 per 1 PO4.? Not sure how accurate that is, but would love to hear some thoughts on this subject as it may help us all.

Happy Reefing!

 

[SPR1968]

I personally try to keep my parameters around 10-15ppm Nitrate and 0.03ppm phosphate

I found high phosphate causes all sorts of issues, like hair algae etc., so I keep it locked down low

Raised nitrate however seems to make the corals glow with health, but up to a point.

I’m currently at around 20 Nitrate and in the process of getting it down. I have a couple of corals that don’t like anything over about 15 and they tell me!

Some of the parameters recommended by Red Sea have raised phosphate around 0.1 so opinions always vary in this hobby but I think the opinion is moving away from ultra low nutrient levels these days.

The Tanks of the masters article illustrate some of this

I seem to remember reading something on the Redfield Ratio and reef tanks and how it applies or not, but can’t remember! Lol. Hopefully someone can help us.

 

[Victoria M]

Hello!

Over the years this has been one of my favorite subjects. A while back I noticed my tanks doing a lot better with more NO3 than PO4.

When the NO3 matched the PO4 on the lower side the tank begin to grow hair algae in the sump, and dark brown algae on the rocks, overflow box, sand-bed and glass.

First let’s look at those low numbers. PO4 was down to 0.02-0.03ppm and NO3 was 1ppm.

As I bumped the the NO3 up to 3ppm...the algae begin to decrease. It continued to decrease even more as I slowly bumped it to 6ppm. Right now I’m holding it at 10ppm and the tank looks great.

I also increased the PO4 to 0.07ppm. This really got me thinking about the Red Field Ratio. Off the top of my head I think I heard you’re supposed to have 16 NO3 per 1 PO4.? Not sure how accurate that is, but would love to hear some thoughts on this subject as it may help us all.

Happy Reefing!

I just watched the BRS video on this last night. It said exactly what you said.

 

[Zerobytes]

I personally try to keep my parameters around 10-15ppm Nitrate and 0.03ppm phosphate

I found high phosphate causes all sorts of issues, like hair algae etc., so I keep it locked down low

Raised nitrate however seems to make the corals glow with health, but up to a point.

I’m currently at around 20 Nitrate and in the process of getting it down. I have a couple of corals that don’t like anything over about 15 and they tell me!

Some of the parameters recommended by Red Sea have raised phosphate around 0.1 so opinions always vary in this hobby but I think the opinion is moving away from ultra low nutrient levels these days.

The Tanks of the masters article illustrate some of this

I seem to remember reading something on the Redfield Ratio and reef tanks and how it applies or not, but can’t remember! Lol. Hopefully someone can help us.

How do you control the numbers to that accuracy? I finally got NO3 down from 50 to about 3. But PO4 was 0 (per Hanna) and got that up. Now PO4 seems too high (.13). Granted I really don't know what I'm doing and just looking where I can have both in the ballpark and not worry too much about it.

 

[SPR1968]

How do you control the numbers to that accuracy? I finally got NO3 down from 50 to about 3. But PO4 was 0 (per Hanna) and got that up. Now PO4 seems too high (.13). Granted I really don't know what I'm doing and just looking where I can have both in the ballpark and not worry too much about it.

It’s just a balancing act

I use a combination of Nopox Seachem Matrix, Marine Pure, Purigen..... and other methods to keep everything under control

 

[Reefahholic]

I personally try to keep my parameters around 10-15ppm Nitrate and 0.03ppm phosphate

I found high phosphate causes all sorts of issues, like hair algae etc., so I keep it locked down low

Raised nitrate however seems to make the corals glow with health, but up to a point.

I’m currently at around 20 Nitrate and in the process of getting it down. I have a couple of corals that don’t like anything over about 15 and they tell me!

Some of the parameters recommended by Red Sea have raised phosphate around 0.1 so opinions always vary in this hobby but I think the opinion is moving away from ultra low nutrient levels these days.

The Tanks of the masters article illustrate some of this

I seem to remember reading something on the Redfield Ratio and reef tanks and how it applies or not, but can’t remember! Lol. Hopefully someone can help us.

Agree 100%. Not one of those masters runs NO3 under 5. Most are 10+

Phosphate are lower levels seems fine, but like you said...nitrates elevated a bit brings life to my corals.

 

[Js.Aqua.Project]

I believe the Redfield Ratio is 16:1 (N : P).

Edit: had to space out : and P so it wouldn't convert to smily.

 

[Reefahholic]

I just watched the BRS video on this last night. It said exactly what you said.

It’s true!

 

[Reefahholic]

It’s just a balancing act

I use a combination of Nopox Seachem Matrix, Marine Pure, Purigen..... and other methods to keep everything under control

I use Siporax to better control Nitrates and Slowly bring down PO4 with Phosphate RX or SeaKlear Commercial- LaCI. If they’re reading Zero...I dose PO4 or increase feeds. I dose Loudwolf NaNO3 to keep NO3 where I like it.

 

[Reefahholic]

I believe the Redfield Ratio is 16:1 (N : P).

Edit: had to space out : and P so it wouldn't convert to smily.

I think you’re right. Hard to believe it’s that high.

Would seem like 8:1 (N) Or 10:1 (N) would be more reasonable. Maybe Randy could weigh in on why they’ve calculated it so high.

 

[Js.Aqua.Project]

I think you’re right. Hard to believe it’s that high.

Would seem like 8:1 (N) Or 10:1 (N) would be more reasonable. Maybe Randy could weigh in on why they’ve calculated it so high.

If I remember correctly it is the average of N : P in the deep ocean and phytoplankton.

 

[Eagle_Steve]

For ratio, I have never really looked much into the redfield aspect. I was on the opposite end of a lot of people and have to dose nutirents heavily (there is only so much you can feed fish lol), so once the tanks looked good. I kept them there for a bit and then adjusted one or the other ever so slightly.

My tanks I have found 10-15 for NO3 and .06-.1 for PO4 is the happy medium. My corals all look good and have better color then just running it at ultra low nutrients.

 

[Reefahholic]

For ratio, I have never really looked much into the redfield aspect. I was on the opposite end of a lot of people and have to dose nutirents heavily (there is only so much you can feed fish lol), so once the tanks looked good. I kept them there for a bit and then adjusted one or the other ever so slightly.

My tanks I have found 10-15 for NO3 and .06-.1 for PO4 is the happy medium. My corals all look good and have better color then just running it at ultra low nutrients.

100% agree Steve.

 

[BeejReef]

After mighty struggles, I've been able to get detectable Nitrate and Phosphate (.5N and .04P) and my corals... particularly softies... look MUCH happier.
With a new tank, it's been a real chore to tune it in.. skimmer, no skimmer, length of photoperiod on chaeto, how much chaeto to remove..

The plan now is to let the chaeto continue to overgrow my refugium space until there is some ongoing die-off. I'm theorizing that the die off should release redfieldish ratios and from there I can simply refine the length of photoperiod. Either way, I'm glad to have detectable levels. LPS and SPS were doing ok, but I had a shroom and zoas that were in decline. Had to set the skimmer to simply overflow and cut back to a 9 hour fuge photoperiod to get there.

 

[Reefahholic]

After mighty struggles, I've been able to get detectable Nitrate and Phosphate (.5N and .04P) and my corals... particularly softies... look MUCH happier.
With a new tank, it's been a real chore to tune it in.. skimmer, no skimmer, length of photoperiod on chaeto, how much chaeto to remove..

The plan now is to let the chaeto continue to overgrow my refugium space until there is some ongoing die-off. I'm theorizing that the die off should release redfieldish ratios and from there I can simply refine the length of photoperiod. Either way, I'm glad to have detectable levels. LPS and SPS were doing ok, but I had a shroom and zoas that were in decline. Had to set the skimmer to simply overflow and cut back to a 9 hour fuge photoperiod to get there.

Yeah, it’s hard. I feel your pain. It’s such a delicate balance. Then when the Cheato and Corals grow into colonies, it’s hard to keep detectable levels. So expect that, but when the corals are showing good color and their not pale or fading out...no need to worry. Make sure you have a couple indicator corals that you know exactly their colors when their healthy so that if you have zero readings and notice those getting pale..it’s time to supplement some nutrients or nutrition.

 

[BeejReef]

Yeah, it’s hard. I feel your pain. It’s such a delicate balance. Then when the Cheato and Corals grow into colonies, it’s hard to keep detectable levels. So expect that, but when the corals are showing good color and their not pale or fading out...no need to worry. Make sure you have a couple indicator corals that you know exactly their colors when their healthy so that if you have zero readings and notice those getting pale..it’s time to supplement some nutrients or nutrition.

Just trying to hold it together for the first 6mo's-1yr and find some stability.. lol. I was so worried about algae overrunning the DT. Atm, I'm opening the blinds and turning up the whites so I don't starve my cleanup crew.
The great refugium awakening really seems to have transformed the hobby... almost overnight

 

[ajhudson15]

im running my po4 at 0.06 and nitrates at 6ppm and everything is looking good. still raising my nitrate little by little to I get to the 10 mark. I also dose loudewolf nitrate and it works great

 

[Dan_P]

Hello!

Over the years this has been one of my favorite subjects. A while back I noticed my tanks doing a lot better with more NO3 than PO4.

When the NO3 matched the PO4 on the lower side the tank begin to grow hair algae in the sump, and dark brown algae on the rocks, overflow box, sand-bed and glass.

First let’s look at those low numbers. PO4 was down to 0.02-0.03ppm and NO3 was 1ppm.

As I bumped the the NO3 up to 3ppm...the algae begin to decrease. It continued to decrease even more as I slowly bumped it to 6ppm. Right now I’m holding it at 10ppm and the tank looks great.

I also increased the PO4 to 0.07ppm. This really got me thinking about the Red Field Ratio. Off the top of my head I think I heard you’re supposed to have 16 NO3 per 1 PO4.? Not sure how accurate that is, but would love to hear some thoughts on this subject as it may help us all.

Happy Reefing!

Hard to understand how adding increasing nutrient levels or maintaining a certain nutrient ratio prevents nuisances algae growth. The notion is definitely popular, but there are simply too many uncontrolled variables and less than objective observations by proponents for me to have any confidence in these ideas.

 

[ScottR]

Just thought I’d share this: I took a sample of water from the ocean. A bit offshore. I tested using Salifert kits. PO4 was almost immeasurable as was NO3. But we are not running a ocean in our tanks.

 

[Nano sapiens]

Just thought I’d share this: I took a sample of water from the ocean. A bit offshore. I tested using Salifert kits. PO4 was almost immeasurable as was NO3. But we are not running a ocean in our tanks.

That is true. Corals in nature obtain a lot more nutrients from feeding than in the typical reef aquarium, so having very low P and N is typically not an issue out in the wild.