Nitrate Dosing

[Randy Holmes-Farley Verified Community Expert]

Very interesting to see how these processes relate to each other in tanks. I guess then that the coral paste food stuff that I have been adding, expecting it to increase N and P, will have been adding a balanced amount of carbon and the net effect is not an increased level of N and P but an increased bacterial population, and in addition that makes the possibility of trace element imbalance arise (if the food trace element content is different to the skimmate trace element content).

What do you think about dosing of aminos for corals? I believe the zeo people use this to provide N and P to corals in ULNS, I guess the idea is that bacteria won't use up the N and P in amino’s, making them stay in the water for longer so the corals can take the nutrients up, but do you believe that bacteria won't immediately break these aminos down regardless?

And do you think amino’s or free organic carbon are beneficial for SPS corals? Reading one of your articles today on organics I see that natural surface waters (not sure if that includes reefs) have around 150 ppb carbs, 10 ppb amino’s, 150 ppb humic compounds - those figures all sound really low (IE I dose about 2.5 ppm ethanol per day). I'm beginning to wonder about how good DOM is for SPS, what with the information around about bacterial infections causing RTN, and I wonder if all this DOM just feeds it.

Might there be an alternative approach for SPS only tanks where N and P are dosed as salts, or removed with GFO and sulphur nitrate reactors if required, and carbon is kept as low as possible, and would this more closely replicate natural reefs?

Hope thats not too many points for one post Randy!

Cheers, Pete

Yes on the trace elements.

Amino acids seem useful for corals that are in low nutrient systems, maybe in all system, although I've not tried dosing them in my system. It's a good way to add N if that is the goal. If the product contains purified amino acids it won't contain much P, but if it is hydrolyzed protein it might. I do not know if a coral would use it for anything other than acquiring the particular amino acid for protein synthesis. So I don't know if they get energy from it.

I do not know if corals have any problem with ethanol or acetate in the water, so I do not know if an all inorganic approach to nutrient management is better or not.

 

[UK_Pete]

Interesting thanks. I think that explains why my food dosing is not having much effect on my monti which is still looking starved. Maybe should consider dosing nutrient salts in this case.

An all inorganic approach to nutrient management is not something I would jump straight into but its perked my interest, I just read an older article by you 'Nitrate in the reef aquarium' and I wonder if anythings changed since then. Pura nitrate lock claims to be a resin which binds nitrate in marine aquaria and is regenerable (strangely, in strong brine), and also the sulphur denitrifier has 10 more years under its belt and seems to still be around. But I'm a bit confused about hydrogen sulphide production in the sulphur denitrifier. Is it produced under low nitrate conditions as some seem to suggest, and is it true that GFO would convert this back to elemental sulphur?

I was thinking N and P could be dosed throughout the day, and a low flow pump could feed a sulphur denitrifier followed by GFO to maintain N and P at fairly constant levels in a tank perhaps (so every day you have a constant input of nutrients but if the concentration of nutrients went up, with constant flow going to the denitrifier and GFO, and output being at 0 nutrients, it would tend to stabilise nutrients at a certain level).

 

[beaslbob]

I heard some of the balling schemes use small amounts of calcium nitrate.
And I could have heard wrong also.
my .02

 

[playmo]

I add coral food twice a week and dosing "Organic carbon+bacterial" products every day still has algae problem...

i smell some "Organic carbon liquid" products... boths relate as vodka and vinegar... I didn't using pellet products coz it is hard to control the volume and need a reactor to running it
I am just a beginner to use chemical products in coral tank, It can reduce N and P effectively, but it produces other algae that I hvn't seen before like"dark film".
Even N is 0, P under 0.03.... rocks are still dark, algae still everywhere.

1.5yrs tank
36"x18"x20" main tank with sump tank =280L
lighting: AI vega+AI Hydra(0% red, 10% green others 90% for 7 hrs), UV VHO Super Actinic Blue x2 for 4hrs
Skimmer: jetskim120
Dosing: FM balling method, NYOS pure Iodine
NYOS method except ZEO(start from 2 months ago)

Fighting with Algae and Aiptasia
Headache of some SPS become darker

 

[furam28]

Sorry for reviving an old thread but there's some great info here that is quite relevant to my situation.

@Randy Holmes-Farley . Quick question. Will HPO4(2-) dissociate to PO4(2-) in a reef tank? I need to dose phosphate, and I have access to sodium phosphate dibasic (Na2HPO4). The pKa for HPO4 -> PO4 is close to 12.

Here's my situation: I have been carbon dosing (NO3POX) for close to 6 months using auto-doser. For the last 2 months or so both my nitrate and phosphate have been undetectable (red sea pro for nitrate, and Hanna ultra low phosphorus for phosphate). I dose 3.5mL Nopox daily (40g total system volume). My tank is clean and algae free. My zoas Some of my SPS are a little faded, so 2 weeks ago after some reading I decided to start dosing sodium nitrate (food grade). I dosed 1ppm nitrate daily for 5 days but my nitrates stayed at 0.25ppm the whole time. I'm guessing due to the carbon dosing the nitrate I was dosing was getting consumed rapidly by the bacteria. I kept dosing nitrate at 1ppm for another week, and all of a sudden I noticed some burnt tips, and some of my SPS not looking happy. I immediately tested and my nitrate was now at 4ppm. What I think happened was that at some point, the trace amount of phosphate in my system got stripped and phosphate became limiting. That's when nitrate started slowly climbing. I tried doing water changes and feeding heavily to bring my phosphate back in balance but my nitrate keep rising and I detect no phosphate. At this point I think I need to slowly dose phosphate for a week or so to bring the nitrate : phosphate ratio back in balance where I can stop dosing either and continue with just carbon dosing and heavy feeding. I plan on dosing phosphate at 0.02ppm per day until I start detecting phosphate.

@Keithcorals . You mentioned that you dose both nitrate and phosphate when you need to. Do you think I am in the right track? Any advice will be greatly helpful.

Here's my tank parameters:

tank size: 20g long with 25g sump
livestock: 5 fishes (2-3 inches each)
mixed reef: sps, lps and softies
24 hour skimmer. bubble magus curve 5.
chaeto in dedicated 5-gallon section with 16 hour/day light
kalk dosing with ato

cal: 400
alk: 8-9 dkh
nitrate: currently at 4ppm (used to be <0.25ppm)
phosphate: 0ppm
pH: 8.1 (day) 7.8 (night)

Any experience or advice from ULN folks here will be greatly helpful. Overall my tank is still healthy but a few of my SPS have lost color and are showing burnt tips. My softies and LPS are all quite happy though (I'm guessing they are content with the high nitrate and the spot feeding).

 

[DMan]

Why dont you just cut back on the carbon dosing.

 

[furam28]

Why dont you just cut back on the carbon dosing.

Forgot to mention that. I cut down NoPox dosing from 3.5mL per day to 2.4mL per day. Its been 3 days and nitrate rose a little but not phosphate. I'll do a few water changes and see if that helps bring nitrate down to proportionate level and maybe cut down Nopox further.

 

[DMan]

I use the nopox as well, and once your levels drop you can really cut back on it. Like 0.5ml/25g. And then that remains your maintenance dosage. And then from there you can fine tune it as the system changes over time.

 

[jaydogg76]

What about mecoral?

 

[furam28]

What about mecoral?

What about it?

 

[furam28]

I use the nopox as well, and once your levels drop you can really cut back on it. Like 0.5ml/25g. And then that remains your maintenance dosage. And then from there you can fine tune it as the system changes over time.

Ok. That's great to know. I just cut down my dosage to 1.6mL / day. Will test for a few days and will cut down further in a week if need to. Hopefully my algae stays under control.

 

[jaydogg76]

What about it?

Has anyone tried it. If so what's the difference with other products

 

[scottbapilot]

I run a gfo reactor and my phosphate's are undetectable.

 

[grim1reaper72]

I have always had a carbon pad in my wet/dry my nitrates are undetectable and my po is less than .25 I have just started in with corals and noticed they didn't have much color and I stumbled upon this thread and it has me thinking I shouldn't have a carbon pad so it would increase my nitrates. Am I correct in thinking that?

 

[grim1reaper72]

Sorry I have a 55 gal with 2.5 gal refugium full of chaeto

 

[furam28]

I have always had a carbon pad in my wet/dry my nitrates are undetectable and my po is less than .25 I have just started in with corals and noticed they didn't have much color and I stumbled upon this thread and it has me thinking I shouldn't have a carbon pad so it would increase my nitrates. Am I correct in thinking that?

By carbon pad you mean GAC (the black activated carbon)? That's something else. Here we are talking about "carbon dosing", which is basically vodka (or vinegar) dosing, or No-pox dosing, or running a biopellet reactor, or zeovit.

 

[Randy Holmes-Farley Verified Community Expert]

Has anyone tried it. If so what's the difference with other products

Which product? They sell high quality products, but so do many companies.

 

[Randy Holmes-Farley Verified Community Expert]

@Randy Holmes-Farley . Quick question. Will HPO4(2-) dissociate to PO4(2-) in a reef tank? I need to dose phosphate, and I have access to sodium phosphate dibasic (Na2HPO4). The pKa for HPO4 -> PO4 is close to 12.

All of the forms of phosphate in seawater equilibrate essentially instantly, so you can dose any form you want (H3PO4, H2PO4-, HPO4--, PO4---).

The only real difference is that adding some will add alkalinity (PO4--- and a small amount from HPO4--) and some will deplete alk (H3PO4, and a small amount from H2PO4-).

I think dosing it is a fine plan.

 

[Randy Holmes-Farley Verified Community Expert]

I have always had a carbon pad in my wet/dry my nitrates are undetectable and my po is less than .25 I have just started in with corals and noticed they didn't have much color and I stumbled upon this thread and it has me thinking I shouldn't have a carbon pad so it would increase my nitrates. Am I correct in thinking that?

I wouldn't remove it if you mean the black activated carbon. Carbon (granular activated carbon) will not have a big nitrate reduction effect (it doesn't bind any, but will bind and does a good job of removing organics which can yellow the water and can be toxic.

FOr nitrate reduction, folks are typically referring to organic carbon, such as is present in vodka or vinegar.

 

[Randy Holmes-Farley Verified Community Expert]

I run a gfo reactor and my phosphate's are undetectable.

Just make sure it isn't reducing phosphate too much or some corals may begin to suffer.