How stable does nitrate & phosphate have to be?

[kwirky]

I'm dealing with a nutrient deficiency in my tank and have resorted to daily dosing 2ppm worth of nitrate (with potassium nitrate) and dosing 0.2ppm worth of phosphate (with potassium phosphate), daily. It's 500L of water volume and I'm adding 2g of kno3 and 0.2g of kpho3. I'm adding them dry to the sump, like how I used to dose my high tech planted tanks.

When I add it in the tank it's completely consumed 24 hours later (hanna checkers) so I'd like to up the amount I dose until I no longer see it hitting the zero point 24 hours later. However, I am worried about the nitrate bouncing up and down due to adding it and it getting removed, and what the spikes upwards in nitrate can do to fauna within the tank. Is that something to be concerned about? Or is dumping 5ppm nitrate and 0.5ppm phosphate in my tank each night ok for the inverts and corals?

 

[Crustaceon]

Are you running a skimmer or refugium/algae turf scrubber?

 

[ForTheLoveOfCoral21]

Dosing nutrients in an aquarium requires careful consideration to maintain a stable and healthy environment for your tank inhabitants. While it's important to address nutrient deficiencies, it's equally important to avoid excessive fluctuations and potential negative impacts on the fauna and corals.

Adding 5ppm nitrate and 0.5ppm phosphate each night can lead to significant nutrient spikes and subsequent removal, which may cause stress to the tank inhabitants and disrupt the balance of the ecosystem. Sudden changes in nutrient levels can affect coral health, lead to algae outbreaks, or cause other water quality issues.

Instead of increasing the dosing amount until it no longer hits zero 24 hours later, it's recommended to take a more gradual approach. Start by increasing the dosing incrementally, perhaps by 0.5ppm nitrate and 0.05ppm phosphate at a time. Monitor the tank closely, including the behavior and health of the inhabitants, as well as algae growth. Observe how the nutrient levels stabilize and adjust the dosing as needed.

Regular water testing is crucial to evaluate the nutrient levels, ensuring they remain within acceptable ranges. It's advisable to follow established guidelines for nutrient levels specific to the types of corals and invertebrates in your tank.

Additionally, consider other factors that may contribute to nutrient deficiencies, such as proper feeding, water flow, and filtration. Addressing these factors alongside nutrient dosing can help create a more stable and balanced environment for your aquarium.

 

[kwirky]

My skimmer is set to not skim anything, not overflow into the cup because of the nutrient deficiency I've had for a long time. It's basically just acting as an aerator. No chaeto or anything like that.

 

[Dan_P]

I'm dealing with a nutrient deficiency in my tank and have resorted to daily dosing 2ppm worth of nitrate (with potassium nitrate) and dosing 0.2ppm worth of phosphate (with potassium phosphate), daily. It's 500L of water volume and I'm adding 2g of kno3 and 0.2g of kpho3. I'm adding them dry to the sump, like how I used to dose my high tech planted tanks.

When I add it in the tank it's completely consumed 24 hours later (hanna checkers) so I'd like to up the amount I dose until I no longer see it hitting the zero point 24 hours later. However, I am worried about the nitrate bouncing up and down due to adding it and it getting removed, and what the spikes upwards in nitrate can do to fauna within the tank. Is that something to be concerned about? Or is dumping 5ppm nitrate and 0.5ppm phosphate in my tank each night ok for the inverts and corals?

Adding dry reagents to the system is not standard practice. It might not matter for nitrate but for phosphate a definite No-No because of the possibility (slim) of precipitation. Break the habit now. Dose solutions.

I am going to guess that you have a new aquarium. Bouncing phosphate and nitrate concentrations have not been demonstrated to be an issue at this time in an aquarium’s existence, or for that matter, any time.

 

[kwirky]

It's not new but it's not old either, and it's always had low nutrients issues, so it doesn't spend much time out of the uglies.

I'll mix up some solution with the two and add it to a dosing channel but the line will get gross after a little while. What's the chemical reaction which can cause the dry potassium to precipitate? Wouldn't it just precipitate if i mixed a concentrated solution into the tank as well?

 

[Dan_P]

It's not new but it's not old either, and it's always had low nutrients issues, so it doesn't spend much time out of the uglies.

I'll mix up some solution with the two and add it to a dosing channel but the line will get gross after a little while. What's the chemical reaction which can cause the dry potassium to precipitate? Wouldn't it just precipitate if i mixed a concentrated solution into the tank as well?

Calcium phosphate is a possible precipitate when adding solid.

The rapid depletion of phosphate and nitrate is typically seen in new systems. For some folks, a 1 year old system is new.

 

[Tavero]

It's not new but it's not old either, and it's always had low nutrients issues, so it doesn't spend much time out of the uglies.

I'll mix up some solution with the two and add it to a dosing channel but the line will get gross after a little while. What's the chemical reaction which can cause the dry potassium to precipitate? Wouldn't it just precipitate if i mixed a concentrated solution into the tank as well?

Calcium can react with phosphates to Calcium phosphate which is insoluble in water. Solutions are getting diluted faster so the chance for percipitation is lower.

 

[kwirky]

The tank was an upgrade of an existing system, just before covid, then i caught covid bad 2x and it crashed each time due to inability to keep on top of it. It crashed another time last November when i got into a car accident and I'm just able to start carrying buckets this month so there's a lot of catch up.

I just mixed 175g kno3 and 18g potassium phosphate in 8L water and am dosing it with the the dosing pump now, to keep it steady and avoid precipitation like suggested. I wanted to add dry ferts at first until i figured out my maintenance amount, because the math is easier, but I'll go with this for now. I'm dosing 40mL per day: 1ppm nitrate, and 0.1ppm phosphate. We'll see how it goes, I'll keep upping it until it starts to build up isn't 100% consumed, then back it off a bit.

I lost a bunch of my acros but my kh, calcium, and magnesium have been steady and balanced for 6 months (dosing aquaforest 123). I removed most of my sand (left a few litres for the wrasse). I've dialed back my lighting from 325 par throughout the tank to 250 (and 350-400 peaks in two 6x6" areas) to cut down on nutrient usage.

I'm hoping this makes a large difference. It'll be slow to observe changes and i don't want to change much else at the same time. The acro die off has slowed down since i dialed back the lights.

 

[Randy Holmes-Farley]

I do not recommend potassium nitrate unless it is very short term. Too much rise in potassium. Sodium nitrate or calcium nitrate are both cheap and available, and are much better choices.

I also see no reason to not dissolve these materials in RO/DI water before dosing them, if for no other reason than being sure that undissolved particulates do not land on, or get taken into, delicate organisms.

 

[k2-]

Lets not be sticky about numbers though -

Kwirky - quick question - are corals growing or you see sign of starvation (LPS are the first one to let you know if they dont have enough food - and specially mushrooms). Alot of times the readings are not really 0 - which means the nitrates produced is nitrates consumed by overall eco system (and hence phosphates in proportion).

Assuming you are seeing distress in coral - i will say try natural ways (add more fish) and adjust your nutrient export (run your reactors only part of the time or 0 ) or switch off refugium lights for few days and observe.

My tank shows 0 nitrates and lower phosphates - but all my growth is fine and corals are happy - I have upstocked the fish this week so will keep an eye but I would (personally) do not resort to dosing as permanent long term solution.

 

[KTTX]

I do not recommend potassium nitrate unless it is very short term. Too much rise in potassium. Sodium nitrate or calcium nitrate are both cheap and available, and are much better choices.

I also see no reason to not dissolve these materials in RO/DI water before dosing them, if for no other reason than being sure that undissolved particulates do not land on, or get taken into, delicate organisms.

@Randy Holmes-Farley if i am dosing Calcium and Alkalinity using your DIY, can i add in little Phosphate to one of these in my dosing container? Thanks

 

[Randy Holmes-Farley]

@Randy Holmes-Farley if i am dosing Calcium and Alkalinity using your DIY, can i add in little Phosphate to one of these in my dosing container? Thanks

You can add it to the alk part.

 

[kwirky]

Lets not be sticky about numbers though -

Kwirky - quick question - are corals growing or you see sign of starvation (LPS are the first one to let you know if they dont have enough food - and specially mushrooms). Alot of times the readings are not really 0 - which means the nitrates produced is nitrates consumed by overall eco system (and hence phosphates in proportion).

Assuming you are seeing distress in coral - i will say try natural ways (add more fish) and adjust your nutrient export (run your reactors only part of the time or 0 ) or switch off refugium lights for few days and observe.

My tank shows 0 nitrates and lower phosphates - but all my growth is fine and corals are happy - I have upstocked the fish this week so will keep an eye but I would (personally) do not resort to dosing as permanent long term solution.

I had a crash after the accident. Since then, my red plating monti grows like mad, I remove a 1L container worth every 3 months, even with my nutrients tested at zero. My acros aren't really growing like they used to. I used to get an inch every few months but I've only had about 1/4 inch over the last few months, so when the acros end up in poor health they die back.

After less than 7 days of potassium nitrate dosing my acros got these bulbous tips, their growth exploded at the tips, like miracas, so I suspect I have a definite nutrient deficiency.

This thread's about stability of dosing nitrate, though, which was determined in the discussion that it's not a big deal. What is a big deal is dosing potassium nitrate over time so I had to end the dosing unfortunately.

@Randy Holmes-Farley : This is the nitrate I can source, calcium nitrate from Amazon.ca. The manufacturer states there's ammonia in it. Is the 1% ammonia a big problem if I'm dosing it slowly via a dosing pump? You'd think that my nitrifying bacteria would be able to handle it (I have two 8"x8"x4" marinepure blocks for my 525L system), if the dosing was very steady, such as 24x per day from the dosing pump, right? Could this be a viable nitrate source? I'd have to calculate the calcium added (from CaN2O6) and drop my calcium dosing, right? (I'm capable of these molecular weight calculations)

 

[Reefahholic]

I don’t like my PO4 swinging more than .05, and NO3 more than 2-3 ppm.

 

[Randy Holmes-Farley]

I had a crash after the accident. Since then, my red plating monti grows like mad, I remove a 1L container worth every 3 months, even with my nutrients tested at zero. My acros aren't really growing like they used to. I used to get an inch every few months but I've only had about 1/4 inch over the last few months, so when the acros end up in poor health they die back.

After less than 7 days of potassium nitrate dosing my acros got these bulbous tips, their growth exploded at the tips, like miracas, so I suspect I have a definite nutrient deficiency.

This thread's about stability of dosing nitrate, though, which was determined in the discussion that it's not a big deal. What is a big deal is dosing potassium nitrate over time so I had to end the dosing unfortunately.

@Randy Holmes-Farley : This is the nitrate I can source, calcium nitrate from Amazon.ca. The manufacturer states there's ammonia in it. Is the 1% ammonia a big problem if I'm dosing it slowly via a dosing pump? You'd think that my nitrifying bacteria would be able to handle it (I have two 8"x8"x4" marinepure blocks for my 525L system), if the dosing was very steady, such as 24x per day from the dosing pump, right? Could this be a viable nitrate source? I'd have to calculate the calcium added (from CaN2O6) and drop my calcium dosing, right? (I'm capable of these molecular weight calculations)

The possible issue with that material is purity, which the label posted doesn't indicate. If you can get food grade calcium nitrate, it's a good choice. if not, go with food grade sodium nitrate.

 

[blecki]

Add a refugium if you can and turn the skimmer back on. Yes yes, trying to raise nutrients, great. But phosphate and nitrate aren't the only things the skimmer is removing. A refugium will help you control the level by taking up any excess you overdose. It will also eventually eliminate the need to dose entirely once it's overgrown and the bottom layers of algae start to die off.

People seem to forget that algae is part of the ecosystem corals thrive in.

 

[Dennis Cartier]

Being in Canada, you will have trouble getting the dry nitrate additives that are common in the US. I would suggest the E.S.V B-Ionic Nitrate, which is a calcium nitrate solution. Definitely not as inexpensive as the dry version, but you will probably not use too much over time, so not too bad as an expense.

 

[Lasse]

I do not recommend potassium nitrate unless it is very short term. Too much rise in potassium. Sodium nitrate or calcium nitrate are both cheap and available, and are much better choices.

I have been dosing potassium nitrate in the past but I have also run into K levels over 500 mg/L and its not healthy for fish - I have got 2 occasions of suddenly fish death in these concentrations- which I suspect has with the K concentration to do. I strongly support Randy´s advice here nowadays. Here in Europe - we can get sodium nitrate in the grocery store as Chile saltpetre (NaNO3). My standard is 40 g to 500 ml of RO water. 1ml of this solution in 100 L of water will rise NO3 concentrations with app 0.5 mg/L

Sincerely Lasse

 

[kwirky]

Being in Canada, you will have trouble getting the dry nitrate additives that are common in the US. I would suggest the E.S.V B-Ionic Nitrate, which is a calcium nitrate solution. Definitely not as inexpensive as the dry version, but you will probably not use too much over time, so not too bad as an expense.

Yeah i looked into getting it but haven't found anybody in Calgary who sells it so the shipping charges make it expensive. It's basically shipping water, which is costly.