Refugium and the risk of reducing nitrates too much

[lbacha]

I believe cheato also will also consume ammonia before it ever turns into nitrates further reducing the chance of their being detectable nitrates. In my tank I started my cycle with a large ball of cheato and never saw any detectable ammonia, nitrites or nitrates even though I fed the tank food to boost the cycle. I attributed it to the cheato.

 

[Randy Holmes-Farley]

I believe cheato also will also consume ammonia before it ever turns into nitrates further reducing the chance of their being detectable nitrates. In my tank I started my cycle with a large ball of cheato and never saw any detectable ammonia, nitrites or nitrates even though I fed the tank food to boost the cycle. I attributed it to the cheato.

It is certainly true that macroalgae can take up ammonia. Many species even "prefer" it to nitrate.

In the end,however, I'm not sure any ordinary reefer can really know what form is actually taken up, or, for that matter, why it would matter. The end result is identical whether it takes up ammonia or nitrate.

 

[lbacha]

It is certainly true that macroalgae can take up ammonia. Many species even "prefer" it to nitrate.

In the end,however, I'm not sure any ordinary reefer can really know what form is actually taken up, or, for that matter, why it would matter. The end result is identical whether it takes up ammonia or nitrate.

I was more making the comment from the standpoint that if you want nitrates in your tank for sps then adding fish to add ammonia which will turn to nitrates May not work as well with cheato. It is probably better to add nitrates directly which will still be consumed by the cheato but will start in a form usable by your coral.

I agree that in the end it's all the same.

 

[Randy Holmes-Farley]

I was more making the comment from the standpoint that if you want nitrates in your tank for sps then adding fish to add ammonia which will turn to nitrates May not work as well with cheato. It is probably better to add nitrates directly which will still be consumed by the cheato but will start in a form usable by your coral.

I agree that in the end it's all the same.

FWIW, SPS corals can take up ammonia just fine. THey may even prefer it:

Nitrate uptake in the scleractinian coral Stylophora pistillata
https://core.ac.uk/download/pdf/22868201.pdf

from it:


It is rather difficult to compare ammonium and nitrate uptake rates, because few studies have investigated the two nitrogen sources under the same environmental conditions and with the same coral species (D’Elia and Webb 1977; Wilkerson and Trench 1986; Bythell 1990). When maximal uptake rates of nitrate (measured in this study) are compared with the uptake rates of ammonium obtained for the same species under comparable conditions (Grover et al. 2002), we found a preferential uptake of ammonium compared with nitrate (uptake rates of one order of magnitude higher). D’Elia and Webb (1977) as well as Wilkerson and Trench (1986) reached the same conclusions for other scleractinian species and the same trend was also noticed for the symbiotic medusae, Linuche unguilata (Wilkerson and Kremer 1992). Bythell (1990) was the only one to find contrary results, with mean net rates of nitrate uptake exceeding that of ammonium by a factor of two. He explained these results by a variable direction of ammonium flux at low concentrations. His nitrate uptake rates were also 10 times higher than those measured in this study, but a different coral species was investigated, and a different technique was used for uptake rate measurements (in situ depletion). Moreover, the flow might also have been different. Atkinson et al. (1994) indeed demonstrated that the uptake of ammonium may vary by two times during a 10-fold change in water velocity.

 

[lbacha]

Very informative thank you I didn't even think about coral using the ammonia the same way

 

[laverda]

FWIW, SPS corals can take up ammonia just fine. THey may even prefer it:

Nitrate uptake in the scleractinian coral Stylophora pistillata
https://core.ac.uk/download/pdf/22868201.pdf

from it:


It is rather difficult to compare ammonium and nitrate uptake rates, because few studies have investigated the two nitrogen sources under the same environmental conditions and with the same coral species (D’Elia and Webb 1977; Wilkerson and Trench 1986; Bythell 1990). When maximal uptake rates of nitrate (measured in this study) are compared with the uptake rates of ammonium obtained for the same species under comparable conditions (Grover et al. 2002), we found a preferential uptake of ammonium compared with nitrate (uptake rates of one order of magnitude higher). D’Elia and Webb (1977) as well as Wilkerson and Trench (1986) reached the same conclusions for other scleractinian species and the same trend was also noticed for the symbiotic medusae, Linuche unguilata (Wilkerson and Kremer 1992). Bythell (1990) was the only one to find contrary results, with mean net rates of nitrate uptake exceeding that of ammonium by a factor of two. He explained these results by a variable direction of ammonium flux at low concentrations. His nitrate uptake rates were also 10 times higher than those measured in this study, but a different coral species was investigated, and a different technique was used for uptake rate measurements (in situ depletion). Moreover, the flow might also have been different. Atkinson et al. (1994) indeed demonstrated that the uptake of ammonium may vary by two times during a 10-fold change in water velocity.

That is interesting as everything I ever heard up to this point said ammonia was toxic to corals. Or is that they are at levels detectable by most hobby test kits? You learn something new every day.

 

[Randy Holmes-Farley]

That is interesting as everything I ever heard up to this point said ammonia was toxic to corals. Or is that they are at levels detectable by most hobby test kits? You learn something new every day.

It’s the levels that are critical, just as copper is needed in normal amounts and is toxic at elevated levels. [emoji3]

 

[Dan Reef]

Just a quick update:

I've added nitrates and GHA took over the tank, some corals died and others are not happy.

So I decided to change to 2part dosing instead of Triton, shutdown the refugio and go back to I did before that wasn't perfect but worked fine: carbon dosing, bioballs and skimmer.

Thanks!

 

[Randy Holmes-Farley]

Sorry to hear that.

 

[Kscope]

I realize this thread is a few months old but I had to chime in. I have a 54gal corner tank with a 10 gallon sump. Within the sump is a 4 gallon refugium with cheato, a skimmer and return pump. For many years all I have read is the larger the fuge the better.

I have never been able to get my nitrates down below 50. I tried numerous lights, vinegar and alcohol. Lately I have been playing with the light. I finally bought a good and controllable light. The Kessil h80 it has a spectrum control and an intensity control.

On full power and the grow setting my cheato exploded with growth. My nitrates dropped to...you guessed it ZERO. Wow first time ever! So my discovery at least for me was it wasn't the presence of cheato but its growth rate. Is it tied to the spectrum and light intensity?

I recently changed the spectrum away from the pinkish "grow" to a more blue light and reduced the intensity. I did not change the photo period. My nitrates are now sitting at about 5 and have been there for about 3 weeks. There has been no change in the bio load or feeding.

So just looking at this it seems (and I could be totally off base here) that the growth rate (due to light and not nutrients) of the cheato is somewhat proportional to the uptake of nitrate.

If someone else has tried this it would be great to hear. BRS? wink wink...This would be an excellent experiment for the new room.....

 

[Randy Holmes-Farley]

So just looking at this it seems (and I could be totally off base here) that the growth rate (due to light and not nutrients) of the cheato is somewhat proportional to the uptake of nitrate.

That is definitely true. Macroalgae take up nitrate to make tissue. More tissue growth yields more nitrate reduction.

FWIW, low phosphate or low other elements can prevent nitrate reduction with both algae and with bacteria via organic carbon dosing. That sort of limitation is about the only thing that can limit nitrate reduction by organic carbon dosing.

 

[Kscope]

That is definitely true. Macroalgae take up nitrate to make tissue. More tissue growth yields more nitrate reduction.

FWIW, low phosphate or low other elements can prevent nitrate reduction with both algae and with bacteria via organic carbon dosing. That sort of limitation is about the only thing that can limit nitrate reduction by organic carbon dosing.

My phosphates have always been low. < .05