Confusion high or low nutrients

[dfm34]

I am sure this has been asked many times. Some of my sps are browning and I am battling a cyno outbreak. I doubt the pale SPS is from my lights I was running 3x400 MH with 4x80 t5 (just switched to led but problems were preexistent to the switch)

I tried three day lights out and vacuuming while doing a water change with little or no impact Cyno comes back. I was battling high PO4 used GFO and now I figured I stripped the water hence the pale SPS but is counterintuitive to the cyno outbreak which is high nutrients??


Water parameters

Ca 420
Alk 9.3
No3 zero (0)
Po4 .05 (Hanna ulr)
Mg 1250-1300
SG 1.025
PH 7.9 avg

My nutrients appear low which could explain the brown sps but not the cyno?? I have read that the ratio of NO3 to PO4 should be 16:1 so I should have NO3 around .08

So I want to increase NO3 but I don't want to feed the cyno. What should I do to increase color while eliminating Cyno???

 

[dfm34]

Based on some reading I was thinking of starting carbon dosing. Is this the right approach?

 

[Randy Holmes-Farley Verified Community Expert]

My nutrients appear low which could explain the brown sps but not the cyno?? I have read that the ratio of NO3 to PO4 should be 16:1 so I should have NO3 around .08

IMO, that ratio of nutrients is a misunderstanding that some people have, and it seems to be getting worse lately. The Redfield ratio should not (and is not) the ratio of nutrients in the water to attain a certain goal. It is just the ratio of N and P present in organisms such as phytoplankton.

By this way of thinking, if calcium is 420 ppm, then the appropriate amount of alkalinity in the water would be 59 dKH because that's the ratio used by corals.

If the corals are pale (not darkened brown due to excess zoox), adding nitrate may be a reasonable plan. It might spur cyano, but cyano can get N from other sources, including potentially N2 from the air and nitrogen in organics in the water.

There are a number of ways to go after cyano, and if it gets too bad and manual removal isn't sufficient, using an antibiotic might be a reanonable idea. Products such as Red Slime Remover or Chemiclean.

 

[Sallstrom]

We dose nitrate(KNO3) when nitrate goes to near zero(and we usually get some cyanobactreria when NO3 are too low). Within a week or so the cyano goes away and the corals looks better. This has worked well for two of our SPS tanks in our exhibit the last years. I haven't seen any negative effect on SPS corals even if the NO3 goes up to around 10.

You dont need any carbon dosing at this time.

Just measured PAR under our new LEDs in a large tank. Doesn't look that bright but at some spot the PAR were almost 800 ;Nailbiting LED can be stronger than they looks

/ David

 

[dfm34]

Thanks Randy I will disregard the ratio for sure then. As for you and David's suggestion on adding nitrates KNO3 what would you suggest as a source. Or any reading I can review

Thanks Dan

 

[chipmunkofdoom2]

Thanks Randy I will disregard the ratio for sure then. As for you and David's suggestion on adding nitrates KNO3 what would you suggest as a source. Or any reading I can review

Thanks Dan

Some people have used a commercial stump remover to add nitrates. The data sheet for this particular product lists the composition as 100% potassium nitrate (KNO3).

Personally, I don't think I would go this route unless you are very comfortable with your tank's chemistry. In a nutshell, organic carbon dosing and macroalgae use nitrates and a little bit of phosphates as they grow. This is where the Redfield ratio you mentioned above comes in. As Randy said, the actual ratio is not 16:1: that is just how much phosphorus and nitrogen can be found in the organism. In general though, most algae and bacteria seem to use more nitrates than they do phosphates. In some tanks, there is a nutrient imbalance where more PO4 exists than NO3. Reefers will then add nitrates (via KNO3 or other chemicals). With sufficient NO3 available, bacteria or algae can now use the added nitrates and the existing phosphates to grow. The end result is both the nitrates and phosphates are removed.

As I said, I would not attempt this unless you are very comfortable with reef aquarium chemistry and you have an effective nutrient removal strategy in place, such as organic carbon dosing or a large refugium. If you do not export these nutrients shortly after you add them, you could be setting up perfect conditions for a huge algae outbreak in your tank.

Personally, I would stick with the GFO. Cyano tends to like phosphates, so the GFO should take care of the problem over time. Regardless of what your test results are, if you have cyano, you have at least some excess nutrients in the water. I would focus on removing those nutrients instead of adding more.

 

[Sallstrom]

IMO the corals suffer before the cyanobacteria if you try to remove nutrients to get really low values. But I will not go in to that discussion to deep. I'm sure there are a lot of threads on that subject if you search.

We but our KNO3 from a small Swedish webshop for fresh water tanks, but I think you can find it in some grocery stores.

/ David

 

[dfm34]

Some people have used a commercial stump remover to add nitrates. The data sheet for this particular product lists the composition as 100% potassium nitrate (KNO3).

Personally, I don't think I would go this route unless you are very comfortable with your tank's chemistry. In a nutshell, organic carbon dosing and macroalgae use nitrates and a little bit of phosphates as they grow. This is where the Redfield ratio you mentioned above comes in. As Randy said, the actual ratio is not 16:1: that is just how much phosphorus and nitrogen can be found in the organism. In general though, most algae and bacteria seem to use more nitrates than they do phosphates. In some tanks, there is a nutrient imbalance where more PO4 exists than NO3. Reefers will then add nitrates (via KNO3 or other chemicals). With sufficient NO3 available, bacteria or algae can now use the added nitrates and the existing phosphates to grow. The end result is both the nitrates and phosphates are removed.

As I said, I would not attempt this unless you are very comfortable with reef aquarium chemistry and you have an effective nutrient removal strategy in place, such as organic carbon dosing or a large refugium. If you do not export these nutrients shortly after you add them, you could be setting up perfect conditions for a huge algae outbreak in your tank.

Personally, I would stick with the GFO. Cyano tends to like phosphates, so the GFO should take care of the problem over time. Regardless of what your test results are, if you have cyano, you have at least some excess nutrients in the water. I would focus on removing those nutrients instead of adding more.

I am not that comfortable with that. I never did understand stump remover in a reef tank. I will hold off on that one. I think I will put GFO back on line and see what happens.

I am light on fish with only five in a 180. Maybe I will add more. Here is my list.

Maroon clown
Pj cardinal
Melanurus Wrass
Pyramid butterfly
Copperband butterfly

 

[Randy Holmes-Farley Verified Community Expert]

I am not that comfortable with that. I never did understand stump remover in a reef tank. I will hold off on that one. I think I will put GFO back on line and see what happens.

I am light on fish with only five in a 180. Maybe I will add more. Here is my list.

Maroon clown
Pj cardinal
Melanurus Wrass
Pyramid butterfly
Copperband butterfly

There are lots of food grade products you can use. Hobby brands or DIY:

http://www.modernistpantry.com/sodi...MI-52rz4Wo1QIV24izCh23DgLbEAQYASABEgKAuvD_BwE

https://www.etsy.com/listing/222604...MIxNmW5oWo1QIV0IqzCh3ONwLqEAkYBCABEgJdcvD_BwE

 

[dfm34]

There are lots of food grade products you can use. Hobby brands or DIY:

http://www.modernistpantry.com/sodi...MI-52rz4Wo1QIV24izCh23DgLbEAQYASABEgKAuvD_BwE

https://www.etsy.com/listing/222604...MIxNmW5oWo1QIV0IqzCh3ONwLqEAkYBCABEgJdcvD_BwE

That's why your are the master Randy

Thanks